The busiest online shopping time in history has brought a significant increase in visits and revenue over last year. But not only were shoppers out there hunting for the best deals. Web performance experts and the media were out there waiting for problems to happen in order to blog and write about the business impact of sites performing badly or sites that actually went down. We therefore know by now that even though the Apple Store performed really well it actually went down for a short while friday morning.

The question many are asking right now is: What did those that performed strong do right and what did those performing weak miss in preparation for the holiday season?

Learn by Comparing Strong with Weak Performers

We are not here to do any finger pointing but want to provide an objective analysis on sites that performed well vs. sites that could do better in order to keep users on their site. Looking at what sites did right allows you to follow their steps. Knowing what causes weak performance allows you to avoid the things that drag your site down.

Strong Performance by Following Best Practices

JC Penney was the top performer based on Gomez Last Mile Analysis on both Black Friday and Cyber Monday followed by Apple and Dell. For mobile sites it was Sears followed by Amazon and Dell. Taking a closer look at their site allows us to learn from them.

Things they did well to improve performance:

  • Light on 3rd Party Content, e.g.: They don’t use Facebook or Twitter JavaScript Plugins but rather just provide a popup link to access their pages on these social networks.
  • The page is not overloaded with hundreds of images or CSS files. They for instance only have one CSS file. Minifying this file (removing spaces and empty lines) would additionally minimize the size.
  • JavaScript on that page is very lightweight. No long running script blocks, onLoad Event handlers or expensive CSS Selectors. One thing that could be done is merging some of the JavaScript files.
  • Static Images are hosted on a separate cache-domain served with Cache-Control Headers. This will speed up page load time for revisiting users. Some of these static images could even be sprited to reduce download time.

Continue reading the rest of the blog.