As Web sites grow in complexity, the amount of content they host from third party sources continues to climb. “Third party content” refers to any content hosted by a separate company and integrated into a Web site using server-side HTML injection, IFRAME hosting, or a client-side AJAX include.
This trend has its advantages and disadvantages. On the one hand, hosting third party content enables sites to add functionality that might otherwise take them months or years to build themselves. On the other hand, that additional functionality comes at the cost of performance. The more third party content a site hosts, the greater the risk it runs of sluggish load times, request timeouts, and client-side parsing errors. The graphic above is a simple illustration of the potential performance hit you can experience by adding one simple third party widget to your site. I know because these numbers are from my real measurements based on adding a Quora follow me widget. More below…
Let’s examine:
- The types of third party content typically hosted on a Web site
- Assess the performance impact of each type of third party content
- Explore ways sites can manage their third party content for optimal performance
Types of Third Party Content
Advertising comprises a large portion of the third party content found on modern Web sites. Web sites both small and large host third party advertisements to pay for hosting costs, fund staff, and turn a profit. Advertising services are provided by a slew of companies; services include Google AdSense, AdBrite, and Chitika, among many others.
Analytics packages are perhaps the next most popular service hosted off-site. These packages provide detailed visitor analysis and site behavior tracking through a simple piece of code embedded in a Web site’s pages. The most popular packages on the market today are Google Analytics, Omniture, Optify, and VisiStat.
A growing segment of third party hosting belongs to widgets, small content controls that enhance a site with additional services or functionality. The simplest widgets are the social media buttons that many content-oriented Web sites add to their pages to make it easier for users to share popular content on Facebook, Twitter, Google+, and similar services. Widgets can also embed videos, host article feeds from other Web sites, display photos, and enable article comments.
The Impact of Third Party Content on Performance
The impact of hosting third party content on site performance can be summed up in two words: enormous and detrimental.
As a test to see how a widget impacted the performance of the LoadStorm home page, I added a Quora widget to the page that simply allowed people to follow me. No feed or anything highly functional. The results are displayed below. My thanks go out to WebPageTest for their excellent page load analysis and beautiful graphs (the red ovals are mine).
Before adding the widget:
After adding the widget:
Normally, our home page takes a little more than 1 second to reach document complete, but with the widget it took over 4 seconds. Sorry, that doesn’t work for me because I’m too performance conscious. The value of the widget was not high enough to live with the trade-off in poor performance.
I understand that not all widgets will have this much of a negative impact. Maybe not, but I haven’t tried them all. Perhaps that will make for a good blog post next week.
Minimizing the Performance Impact of Third Party Content
Sometimes, companies can realize a performance benefit by changing their business strategies. In the case of ads, for example, a site with even a modest amount of regular traffic can decide to forgo third party ad programs such as AdSense and instead sell space directly to advertisers. Similarly, a company may decide that the performance hit they’re taking on a widget is too severe, and it would be worth investing in a homegrown solution.
Some third party content might not be necessary at all; the drag it creates on performance could negate whatever little value it provides to a Web site. A while back, Joshua Bixby at Web Performance Today urged developers to consider the impact each widget has on their site, and to perform a cost-benefit analysis for each component on a Web page.
If eliminating a third party control isn’t feasible, a company can instead select its third party content providers using performance as one of its selection criteria. A few Web sites exist that track the performance of third party content providers. For example, Steve Souders has a page listing nine of the most popular third party services and widgets, along with their relative performance impact (Small, Medium, or Big). While these numbers are a bit old, Souders has published detailed reports on his tests (see, for example, his report on Glam Media) that explain his analytical and testing methodologies.
Absent independent numbers, development teams can run their own tests using a performance testing tool. Over at dynaTrace, Klaus Enzenhofer suggests implementing a URL parameter that turns off all third party content on a site so that teams can gauge the total impact third party content is having on their performance. This approach can be expanded to turn off selected third party widgets, so that a team can assess the impact individual widgets have on site responsiveness.
Finally, for critical widgets, developers should consult with the widget providers regarding what options exist to optimize hosting. For example, Facebook hosts a page for developers on how to use the channelUrl attribute and asynchronous loading to increase load times for their social plugins.
Conclusion
The ease with which third party content can be added to a Web site sometimes leads site owners to ignore the performance implications of these popular widgets. While it may not be feasible in your situation to eliminate the use of third party content completely, I strong recommend that you actively manage your off-site widgets through judicious selection and regular performance monitoring.
To put it plainly and frankly:
Before you decide whether to use any particular third party content, try it and find out for yourself – measure the decrease in your site’s performance. Is it worth it?
According to industry experts at the Velocity conference, the most popular third party controls on the Web are responsible for between 8 and 15 percent of a page’s total load time. Now consider the data that correlates that increase in page load time to the money you make from your site.
Performance testing statistics compiled on performance-testing.org show that even a single second slowdown in page load times can have a negative affect on site revenue. Other stats:
- Better performing website (speed improvements) increased revenue by 7-12%, increased page views by 25%, and reduced hardware by 50%. – Shopzilla actual stats from a site redesign.
- Google found that an extra 500ms in latency cost them 20% of their search traffic.
- Amazon states that for every 100ms of latency, they lose 1% of their sales.
- 50% of surveyed companies said they lost revenue opportunities because of poorly performing applications. – Aberdeen