You are here: Home page > Computers > e-commerce

Conceptual artwork illustrating the idea of buying things with a computer


No one knows exactly when people first started trading with one another—or how. We do know that metal coins have been used to buy and sell things for at least 2500 years. [1] From horses and handcarts to ships, trucks, and airplanes, the need to trade goods has spurred on innovations in transportation for just as long. Today, though, it's all change: many of us are now buying and selling with a new form of commerce that involves neither money nor transportation—at least not in the traditional sense. You just sit in your armchair, click your mouse a few times, enter your credit card number, and wait for the goods to show up on your doorstep. E-commerce, as this is known, has grown enormously in the last two decades, making life more convenient for consumers and opening up all kinds of new opportunities for businesses. Let's take a closer look at what it is and how it works!

Artwork: Shopping by computer is the basic concept of e-commerce, but it's a bit more subtle than that. Key parts of a retail transaction that once happened in a store (such as inspecting and comparing products and validating a payment card) now have to happen in your home, and fast, affordable, efficient delivery also plays a crucial part in the process. As this illustration shows, you can even buy a new computer with a computer!

Sponsored links


  1. The basic components of an e-commerce system
  2. How e-commerce works
  3. How do you design an e-commerce website?
  4. Using e-commerce to sell information
  5. Advantages and disadvantages of e-commerce
  6. The mobile future of e-commerce
  7. A brief history of e-commerce
  8. Find out more

The basic components of an e-commerce system

Whether you're buying in a store or buying online, everything you do is geared around a transaction: the basic exchange of money for goods or services. In a real-world store, you simply take your new jeans to the checkout, hand over some cash, and leave the store with your purchase in a bag—that's a transaction. It works in a similar way if you're buying online, but there's one important difference: you never actually get to handle (or even see) the goods until they arrive at your home sometime later.

If this makes buying online slightly problematic for the purchaser, it also introduces two extra problems for the retailer (or e-tailer, as online retailers are sometimes known). Apart from having some means of processing transactions online, it means they also need a way of checking that the goods you've ordered are actually in stock, and a means of dispatching and delivering the goods to your address.

In short, then, e-commerce is about combining three different systems: a Web server that can manage an online storefront and process transactions (making appropriate links to bank computers to check out people's credit card details), a database system that can keep a check of the items the store has in stock (constantly updating as people make orders and ideally making new orders with suppliers when stocks run low), and a dispatch system linked to a warehouse where the goods can be instantly located and sent to the buyer as quickly as possible.

Only the first of these three systems is strictly necessary for e-commerce. Many people successfully run small-scale online stores without either complicated databases or dispatch systems: they simply have a website to publicize their business and take orders and then they manage the stock control and dispatch in more traditional ways. Small traders who sell items on the auction website eBay often work in this way, for example. Their "databases" are in their head; their "dispatch system" is simply a walk to the local post office.

How e-commerce works

Here's one example of how a sophisticated, fully computerized e-commerce system might work. Not all e-commerce systems work in exactly this way:

Labelled artwork showing how e-commerce works

  1. Sitting at her computer, a customer tries to order a book online. Her Web browser communicates back-and-forth over the Internet with a Web server that manages the store's website.
  2. The Web server sends her order to the order manager. This is a central computer that sees orders through every stage of processing from submission to dispatch.
  3. The order manager queries a database to find out whether what the customer wants is actually in stock.
  4. If the item is not in stock, the stock database system can order new supplies from the wholesalers or manufacturers. This might involve communicating with order systems at the manufacturer's HQ to find out estimated supply times while the customer is still sitting at her computer (in other words, in "real time").
  5. The stock database confirms whether the item is in stock or suggests an estimated delivery date when supplies will be received from the manufacturer.
  6. Assuming the item is in stock, the order manager continues to process it. Next it communicates with a merchant system (run by a credit-card processing firm or linked to a bank) to take payment using the customer's credit or debit card number.
  7. The merchant system might make extra checks with the customer's own bank computer.
  8. The bank computer confirms whether the customer has enough funds.
  9. The merchant system authorizes the transaction to go ahead, though funds will not be completely transferred until several days later.
  10. The order manager confirms that the transaction has been successfully processed and notifies the Web server.
  11. The Web server shows the customer a Web page confirming that her order has been processed and the transaction is complete.
  12. The order manager sends a request to the warehouse to dispatch the goods to the customer.
  13. A truck from a dispatch firm collects the goods from the warehouse and delivers them.
  14. Once the goods have been dispatched, the warehouse computer e-mails the customer to confirm that her goods are on their way.
  15. The goods are delivered to the customer

All of these things are invisible—"virtual"—to the customer except the computer she sits at and the dispatch truck that arrives at her door.

Sponsored links

How do you design an e-commerce website?

The design of virtual stores is often the most important factor in the success or failure of online businesses. That doesn't simply mean that e-commerce web sites have to look attractive (though they do): they have to be usable (quick and easy to navigate around without irritating or confusing people), reliable (customers expect sites to be online 24 hours a day, seven days a week, and for pages to load without delay), and secure (because no one is prepared to type their credit card details into a website that isn't safe).

Setting up an online store used to be quite an undertaking. Not only did you have to build a dedicated website from scratch, you also had to develop your own merchant system that could securely process credit card details and ship transactions to and from bank computers. These days, anyone can set up an online store in minutes. Websites like PayPal make it possible to build a store very quickly and, since they have built-in credit card processing features, handling transactions couldn't be simpler. Many people set up virtual storefronts on the auction site eBay and then use PayPal (now a part of eBay too) to process their transactions. Some websites (notably Amazon) allow you to incorporate mini versions of their store inside your own website—so you make a small commission selling their products within your own site. For businesses with lots of products that need to combine an easy-to-use website (for users to order from), secure ordering, and a reliable database "back-end" (to manage stock), there are sophisticated content-management systems like Shopify®, Magento®, and WooCommerce® (built on WordPress) that do most of the work for you.

Screenshot of home page working on a desktop, tablet, and mobile

Photo: the world's most successful e-shop. Originally just a bookstore, now it sells almost anything you can imagine. It even allows third-party vendors to sell products alongside its own offerings with something called Amazon Marketplace. Amazon has consistently set the standard for online retailers with pioneering features like one-click shopping. Like every good e-commerce site, it's designed to work equally well on a smartphone (top left), tablet (top right), or desktop/laptop (bottom).

It used to be said that the right domain name was an essential requirement for a successful online business but some of the most memorably named web sites (including, and were early casualties of the 2000/2001 boom and bust. As successful Web businesses such as eBay and Amazon have proved, there doesn't necessarily have to be an obvious connection between the name of a website and things it actually does or sells: all that matters is that, over time, people will come to know, love, and trust the brand and visit the site instinctively when they want to buy something.

Managing how you get your products to your customers is crucially important too: you've only to look at review comments on sites like eBay to see that customers love rapid delivery. That doesn't mean you need your own warehouse and a fleet of delivery trucks, however. Companies like Amazon have built complex and highly efficient warehouse and dispatch systems for their own purposes, which they now allow other people to use as well. Getting someone else to store your products, pick them, and ship them off to your customers, worldwide, is called fulfilment—and it means even tiny companies (or one person running a business from their spare bedroom) can manage deliveries as efficiently and professionally as a much bigger outfit.

Using e-commerce to sell information

There's lots of money to be made online, but not all of this involves selling goods in the traditional way. Many online businesses try to make money by offering a mixture of free and premium services. Yahoo! (which originally stood for Yet Another Hierarchical Officious Oracle), is probably the best-known example of a website like this. Created as a comprehensive directory of other websites, it mutated into a search engine and then a portal, offering a gateway to all kinds of other premium services. For example, you can get free e-mail through Yahoo!, but you can also pay extra for a more sophisticated e-mail system; you can store your photographs for free on Yahoo's Flickr site, but you can pay an extra sum to have them printed out or processed in various ways. (Yahoo has recently sold Flickr, but that's another story.)

Newspapers, magazines, and book publishers also try to make money through a mixture of free and premium services. While most of them offer their basic content (the horrible, unappealing name that online businesses give to the words and pictures they publish) for free, using advertising to make money, some also offer a proportion of their articles for a one-off fixed fee or subscription). Buying an article involves a transaction similar to the ones you'd make on Amazon or eBay, so this kind of online publishing is also clearly a variety of e-commerce.

Advantages and disadvantages of e-commerce

Although early reactions to online shopping websites were often mixed ("It takes too long to find what you want", "I'm not sure they're secure", "The things I want are never in stock", "You can't see what you're buying"), things have improved greatly over the last decade and online businesses have found ways round most of the drawbacks. (For example, some online clothing stores sensibly offer free returns if you don't like the clothes you've bought or if they turn out not to fit.) Many people now swear by online shopping and wouldn't dream of setting foot in a real-world store where prices are often higher, waiting lines are longer, and the doors open only during normal business hours.

Ten large retailers accounted for 68 percent of all U.S. e-commerce sales last year — and Amazon alone represented more than half of all online sales.

The New York Times, March 7, 2021

For businesses too, e-commerce has opened up all kinds of new opportunities. Not many can compete with huge businesses like Amazon or eBay, but anyone can open an online store and start trading within a matter of minutes. Small local stores, long threatened by the growth of giant retailers like Wal-Mart and Tesco, have found a new lease of life by trading online and selling their products mail order.

E-commerce has also threatened many traditional ways of doing business. When people flock to online shopping sites for the Christmas rush, they naturally spend less in real-world stores. Savvy existing businesses such as Wal-Mart have tried to offset the threat by seizing the opportunity: "bricks and clicks" (having real world stores and a seamlessly integrated website) is now generally seen as the way to go. Shoppers have become equally savvy and are adept at inspecting products in real-world stores before buying online, or using websites to locate local branches of stores where they can inspect and purchase exactly the goods they want. It's important to bear in mind that e-commerce still represents only a fraction of all the trade that we do. For the first quarter of 2022, the US Department of Commerce reported e-commerce representing about 14.3 percent of total retail sales, as shown in the chart below, but that figure has remained the same since 2020.

Chart showing the growing of retail e-commerce sales for the last decade, 2013 to 2022
The steady growth of e-commerce: this chart shows how online shopping currently represents about 14 percent of all retail sales—three times as much as a decade ago. More formally, it shows "Estimated Quarterly U.S. Retail E-commerce Sales as a Percent of Total Quarterly Retail Sales: 1st quarter 2013 to 1st Quarter 2022". By courtesy of US Census Bureau.

As ever, customers call the shots and will continue to do so. While some traders (notably car dealers, opticians, and realtors) have tried to resist the threat from online shopping, protectionist tactics are bound to fail in the long term. It's all too easy now for customers to take their money and their spending power somewhere else—even to retailers in another country. The customer, and their mouse, is always right. And always will be.

Sponsored links

The mobile future of e-commerce

If you're running a long-established retail business, chances are you now have a website gathering orders from your customers and processing them through e-commerce. But just as you've got used to the rules of the online game, along comes something new that shifts the goalposts: mobile commerce, also known as m-commerce. You can't help but notice that more and more people are going online through cellphones, iPads, and other handheld devices. Once we hunched over desktop PCs clicking mice; now we're increasingly likely to poke at touchscreen tablets while we slouch on the sofa and simultaneously watch TV.

Screenshot of mobile app on iPod Touch

Photo:'s mobile app running on an iPod Touch.

If you've any doubt about whether m-commerce is the future, you've only to look at the giants of the online world and see how seriously they're taking it. Amazon, Google, and Facebook all see mobile computing as a decisive battleground in the next few years. Google has been highlighting the importance of running a mobile-friendly site for years; way back in a 2012 survey, Google reported that 74 percent of users were more likely to return to mobile-friendly sites and 67 percent were more likely to buy from mobile-friendly sites. However, a massive 96 percent reported that they'd encountered incompatible websites while going online with their mobile. In 2018, market research firm eMarketer made a bullish prediction that retail mobile commerce would rise to $3.556 trillion dollars by 2021, making up almost three quarters of all e-commerce.

One very interesting trend is that mobile site traffic routinely equals or exceeds desktop traffic on weekends (when people aren't sitting at their desks wasting time on their work computers). If you value weekend custom, mobile is where you need to be; if you only have a desktop site, you're potentially losing a lot of custom. Now business customers buying from business sites (so-called B2B ecommerce) might be happy on desktop-only websites. But personal customers, teens with smartphones, and adults browsing at home with smartphones on the sofa fully expect to find themselves using mobile-friendly sites. The ever-increasing importance of mobile explains why Google has now shifted its entire index of the Web to a mobile-first view, in which the mobile version of each website is indexed primarily instead of its desktop version.

What can you do to go mobile?

The first step is to check out how your existing site works on a mobile device (preferably one connected to a cellphone network, and not via Wi-Fi, so you can get a sense of speed as well as usability). There are emulators and testers you can use that simulate mobile devices on a PC (including a great one built into Google's Chrome browser and the open-source Chromium equivalent), but it's much better to get yourself a modern cellphone with a browser or a tablet computer and see how your website works for real. If you've never seen it working on a tiny screen, you might be amazed by how it looks. If your site has been designed to work for a typical widescreen laptop, you'll probably find it looks terrible: columns probably wrap and overlap, the text may be too small to read, links may be too small to click, and so on. Don't worry! once you've assessed the scale of the problem, you can start to do something about it.

There are essentially four options if you want to "go mobile":

  1. Responsive design: Redesign your existing site so that the same HTML code works equally well on both desktop and mobile, using a common stylesheet that has conditional rules in it that apply to devices of different screen width. You can tell when a site is responsive by browsing it on a desktop; if you narrow the width of your browser, the site will suddenly reformat from the desktop to the mobile version. Responsive sites are easy to maintain and search-engine friendly, but they don't always give the best experience for users, because they present essentially the same pages for all users (just formatted differently).
  2. Dynamic serving: Build your pages slightly differently for desktop and mobile devices without changing their URLs (either with a common stylesheet or by "including" an appropriate stylesheet for each device). Typically, you would use PHP or ASP to test for a mobile device and then build a desktop or mobile optimized page, perhaps using a desktop or mobile stylesheet that reformats your common HTML code accordingly. (Or you could use a responsive stylesheet as well.) Dynamic serving is search-engine friendly (providing you signal that the content of your pages varies according to user-agent) and gives a good user experience (because you can optimize pages for desktop and mobile much more than with responsive design), but it can be complex to implement.
  3. Separate mobile site: Detect whether users are on a desktop PC or a handheld device and then redirect to a completely separate mobile version of your site. This means you can optimize your site for mobile users without compromising usability for people on the desktop, but the drawback is having to maintain a second, duplicate version of your site—and the risk of different versions of your pages getting out of step. Remember that search engines such as Google dislike duplicate content, so use techniques like canonical URLs to help them understand where to find the definitive version of each page. If you want, you can set a cookie to remember which version of the site to serve as users hop from page to page. It's a good idea to give mobile users the option to view your desktop site, if they prefer. Separate-URL sites tend to be search-engine unfriendly, but they can give a really good user experience (because the mobile site can be highly optimized for mobile users). One thing to remember: now Google has gone "mobile-first," make sure that a separate-URL mobile site contains all as much content as your desktop site.
  4. Separate mobile app: Develop a free app for mobile devices that effectively bypasses your website altogether. There's an upfront expense in having apps developed, but they generally give a much better user experience than mobile websites. Not only that, but they prevent users getting distracted, clicking other links, and going off to competitor sites. In other words, mobile apps are a great way to "capture" mobile users and keep them.

On top of these, there are evolving methods like AMP (Accelerated Mobile Pages), which allow you to develop a much faster mobile site using a stripped-down subset of HTML (but potentially sacrificing some of your website's features in the process).

Further reading

A brief history of e-commerce

Sponsored links

Find out more

On this website


Practical guides

Popular accounts of successes and failures



  1.    The earliest metal coins are generally dated to ancient Greece c.600–500BCE, although they may have been minted earlier. See The Invention of Coinage and the Monetization of Ancient Greece by David Schaps, University of Michigan Press, 2004, and When Money Talks: A History of Coins and Numismatics by Frank L. Holt, Oxford, 2021. The use of other forms of "money," such as cowrie shells, dates from even earlier, though there's some debate over whether they were really money, ornaments, or both. See Paying With Shells: Cowrie Shell Money Is One of the Oldest Currencies Still Collected Today, Ancient Origins, 26 April 2019.

Please do NOT copy our articles onto blogs and other websites

Articles from this website are registered at the US Copyright Office. Copying or otherwise using registered works without permission, removing this or other copyright notices, and/or infringing related rights could make you liable to severe civil or criminal penalties.

Text copyright © Chris Woodford 2008, 2022. All rights reserved. Full copyright notice and terms of use.

Magento is a trademark of Adobe Inc. Corporation.
Shopify is a trademark of Shopify Inc. Corporation.
WooCommece is a trademark of Automattic Inc. Corporation.
WordPress is a trademark of the Wordpress Foundation.

Follow us

Rate this page

Please rate or give feedback on this page and I will make a donation to WaterAid.

Tell your friends

If you've enjoyed this website, please kindly tell your friends about us on your favorite social sites.

Press CTRL + D to bookmark this page for later, or email the link to a friend.

Cite this page

Woodford, Chris. (2008/2021) E-commerce. Retrieved from [Accessed (Insert date here)]

Can't find what you want? Search our site below

More to explore on our website...

Back to top