Guest comment: Preparing for the Christmas rush – will your site take the strain?

by Sam Patel

If any retailer needs proof of the importance of load testing their web page ahead of major influxes in site traffic, they need only look at this year’s launch of the iPhone 4. The launch day saw Apple.com and the sites of major mobile operators go down for the majority of the day. While Apple is lucky enough that this sort of site performance will not affect sales, most retailers don’t have that luxury.

For the majority of online retail outlets, site outages, freezes and checkout failure mean lost revenue that will likely never be made up. Those losses mount minute by minute, hour by hour, especially during the peak holiday season, when most retailers rack up most of their annual business. During this critical Christmas shopping period, when the site breaks, the bottom line breaks too.

This year, UK retailers have continued to struggle with slow sales as a result of the recession. Online sales will play a huge role this Christmas in helping to bolster total retail figures for the whole year, making it difficult to ignore the real costs in lost revenue as a result of site slowdowns and outages. Site metrics and sales data show the revenue value of every site visitor, and site testing can show the actual cash lost when visitors abandon the site because of poor performance. From previous years, it has been calculated that a traffic spike of 25% beyond a site’s optimum capacity can cost retailers, on average, more than £60,000 in lost revenue every hour.

Mobile commerce hits its stride

Further complicating matters this Christmas is the huge unknown factor of mobile commerce. Experts predict that 10% of Brits will shop on their mobiles this year, and all those smartphones searching for products, comparing prices, and making purchases will be accessing the same back-end databases and applications as all the PC-based browsers, putting even more stress on e-commerce systems.

Getting a fixed line and mobile site into optimal form is the first step to making sure retailers will handle online demand. New features and functionality – such as enhanced product presentation, reviews, and personalisation options – should be well under way, if not complete by now and site owners need to understand exactly how these features and rich content will affect end user experience.

Interactivity, dramatic product presentation and perhaps Flash features will help to set retailers apart from the competition. However, a heavy load of features and functionality can drag site performance down, often because of third-party content, and, instead of enticing visitors; can drive them to leaner, faster competitor sites.

This is also the case for mobile sites. Successful retailers this year will have built mobile into their strategy right from the start – not just as an afterthought to the ‘main’ site, but side-by-side with it. Because of the inherent slowness of mobile networks and devices, mobile sites need to be even leaner than fixed line Web sites. This requires some hard decision-making and analysis of what is essential for users when they are browsing on the go and what it takes to satisfy them, including their need for speed.

To provide an optimal mobile offering, retailers should consider how many elements they want to have on a mobile page such as backgrounds, button pads and graphics. Where 40 to 50 elements are advisable for wired Web, having only 8 to 10 elements is optimal for a mobile page. These large differences highlight the importance of building a mobile site from scratch, rather than attempting to scale down an existing Web site.

Where to begin?

Understanding the site’s bottom line – how much traffic it can handle right now – is the logical starting point to begin understanding how much work needs to be done. Then, projections need to be made for how much traffic and sales are expected for the Christmas period. Although consumer behaviour is difficult to project, especially in these times of continued economic turbulence, whatever the traffic and sales projections, it’s up to IT and the web team to make sure the site can handle any unexpected surge in site visitors.

Many, if not most, retailers still fail to account for mobile in their traffic projections, and that could be a bigger mistake than ever this year. Visitors logging on from mobile devices are calling on the same resources and databases as visitors coming through PC browsers, and so are adding to overall site load. Making matters worse is that those mobile connections are extremely slow; traffic coming in through mobile actually holds the connections longer, and consumes more than its share of resources.

The importance of load testing

Once these predictions have been made, load testing is an effective way of measuring how a site will perform with the anticipated influx of visitors. In a (very oversimplified) nutshell, with load testing you are throwing users at the site until it breaks to check that it can cope with the pressure, and perform optimally for all potential visitors. However, to really understand how a site’s performance will hold up – or not – under holiday stress, and to understand what the experience will be like for users, arrival rate methodology and behaviour models will help to give a more rounded insight into site performance and how consumers will experience the site.

Behaviour modelling results in numerous permutations combining these variables:

• Familiarity: experienced users vs. newcomers

• Connection speed: super-fast FIOS vs. super-slow mobile device, and everything in between

• Latency tolerance: patience of users with slow site response

• Interaction speed: complexity of the page to navigate, and attention level of the user

• Tenacity: willingness of users to stick with a task through completion

Finally, to know how the site will perform for users dispersed across the country or the world, testing must be done over the Internet, from the same geographic locations as your users, not from behind the firewall.

With testing agents dispersed where potential consumers are located, retailers can put together an accurate picture of variations in performance, and overcome the danger of looking at averages. An average page-load time of three or four seconds may seem OK, but that kind of average could mean the site is loading in one second for someone in London, but taking six or more seconds for someone in Sheffield. According to Forrester research, consumers will allow just two seconds for websites to load, and at three seconds, 40% will abandon the site and so delays like this aren’t an option. The solution is to test from multiple, geographically dispersed locations, look at the data, and address any local or regional bottlenecks.

The holiday shopping season is the culmination of many hard hours of work for the IT/web department. And no matter how well things are planned, no matter how rigorously everything is tested, there’s always the chance that the unexpected will happen and something will go wrong. So it makes good sense to have technical personnel on hand and on call during all the critical shopping periods to handle any emergencies, and to have extra computing capacity standing by just in case it’s needed. With this preparation, retailers can spot and correct mobile and Web site performance issues before they affect potential customers. As online shopping offers consumers the ability to freely browse without having to brave the high street, it’s essential that retailers do what they can to stand out from their competitors and don’t risk driving customers to other sites due to poor performance and loading issues.

Sam Patel is technical consultant at Keynote Systems