• by Mark Walsh  @markfwal, October 17, 2014

The ability to precisely target users based on their browsing habits, interests, demographic factors and location has long been a key selling point of online advertising. But the proliferation of cookies, pixels and other tracking devices can come at a cost for publishers whose sites are slowed by third-party trackers.

New research by performance monitoring service Catchpoint Systems suggests that third-party marketing technologies like advertising, analytics and behavioral tracking—meant to help publishers monetize their properties—can actually slow page load times, which in turn can drive customers away.

The Catchpoint analysis examined load times for Web sites in September in four different categories: news, retail, search and travel. News sites tended be the most bloated—in terms of total amount of downloaded bytes for the home page—leading to the slowest average load time among the four categories, at eight seconds. That reflects the full loading of all elements of a page.

Retail and travel sites, on average, took about five seconds to load, and search sites, three seconds. According to separate Catchpoint data, people start to abandon a Web site if it takes longer than five seconds to load. Tags for behavioral tracking, retargeting and site analytics that load with a page all contribute to sluggish performance.

“An organization has no control over third-party Web page elements. So if a Web site has 50 third-party elements, it is dependent on those 50 servers loading fast. That doesn’t always happen,” noted Leo Vasiliou, director of Web performance engineering at Catchpoint.

For news sites in particular, the heavier use of video also plays a part in slowing things down. “Sites like CNN and Bloomberg, for example, are going to have a lot of video clips floating below the fold, said Vasiliou. “So while the user is going to be looking at the primary content, which may or may not be a long time to load, there are several other video files as well below-the-fold.”

Most of the 46 news sites analyzed in the study had user-initiated video rather than auto-play. Some major sites, though, including Yahoo.com. ESPN and USA Today feature auto-play video (and audio) above the fold, which can further slow pages and simply annoy users by forcing them to stop the video if they don’t want to see it.

The Catchpoint study focused on desktop sites, but Vasiliou said news sites tend to load slower than other site categories on mobile devices as well.