"It snuck up on people slowly, this third-party content, until they realized they were in a whole lot of trouble when they tried to optimize the performance of their Web pages and couldn't do it," Karow said.
This "bloat" is caused by the rising number of external elements that Web publishers have loaded their pages with, he said. Those include rich media applications, social media feeds, photos and video coming from content delivery networks and ads.
A site today can have 200 or more of these third-party components, and that trend isn't fading, because end users expect sites to have increasingly richer functionality and content, Karow said.
To stay on stop of the site's performance at Cars.com, Wilson's team uses Web monitoring software and tools from various sources, including Keynote, Google and Yahoo.
With this data, Wilson can make sure that providers of third-party content, ads and gadgets are fulfilling their service-level agreements, and hold their feet to the fire if they're not.
"If you're paying the third party, you can set SLAs and be aggressive about them, because those providers are making revenue off of you," he said.
He finds Google's PageSpeed and Yahoo's YSlow tools very convenient to measure front-end issues, as well as Keynote's Virtual Pages, which dissects pages into their components, letting administrators isolate and identify performance jams.
"You have to make sure you have the right analytics set, and that you're measuring the right things," Wilson said.
If vendor activity is any indication, it seems clear that this issue remains problematic. Google has been growing the Page Speed family of tools and upgrading them regularly, and specialty vendors like Keynote Systems continue sharpening and extending their products. On the same week that Blaze launched its service, another company called Yottaa unveiled a private beta version of a competing cloud-based product.
In Wilson's experience, sometimes the slowdowns caused by external components are only the straw that break the camel's back, and the main problem lies deep within the site's legacy code and design. "In that case, you have to get your hands dirty with the logic that happened over time," Wilson said.
Along the same lines, Web designers and developers need to keep front and center this issue when creating or extending sites. "It's important for Web page developers to put themselves in their customers' shoes and remember that DSL isn't extremely fast, and that many people in emerging markets don't have the connectivity that some people have in Silicon Valley," said Richard Rabbat, a Google product manager who is the product lead for the company's Lets Make the Web Faster initiative.
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