17 Aug 2010
[This post served as the jumping off point for a 30-minute webinar: Three Common Performance Problems Caused by Third-Party Content (And How to Fix Them).]
“Necessary evil” is too strong a phrase when it comes to describing third-party ads, analytics tools, and various other site widgets. But given how much negative talk has been centered around third-party content and web performance lately, it’s not that far off.
Traditionally we have divided the site performance problem into a front-end and back-end problem. It is becoming obvious to me as I speak to more and more customers that we need to refine this high-level taxonomy to include:
- Front end (time that you control)
- Back end
- Third-party content
If your problems are at the front or back end, you have control over them. But if your problem is with third-party content, pretty much your only actionable strategy is to be smart about how you pick your vendors. (If you consider prayer an action, you can also hope and pray that your existing vendors make performance a priority. Meebo and Digg deserve special mention here for doing this, with great results.)
Most of the third-party problems I see fall into three categories:
Problem #1: Tools that promise cool new functionality, but kill your conversion gain
Solution: Conduct a cost-benefit analysis for all prospective tools.
This is something you should do any time you evaluate a new third-party app:
- Perform an A/B test of your site, with and without the tool, in a real-world environment. Generate waterfall charts for both tests, and identify how long the third-party objects take to load. Note these benchmarks.
- From the tool vendor, get the number for the average conversion rate bump experienced by other sites that use the tool.
- Using Aberdeen’s widely accepted performance stat that a 1-second page delay equals a 7% loss in conversions, calculate the potential net conversion gain or loss. For example, if a tool slows down page load by 2 seconds, that means a 14% conversion loss. But if that same tool promises a 20% conversion increase, then that’s a net gain of 6% (not including the cost of purchasing the tool).
Problem #2: Badly optimized ads
Here’s another client example. One company we helped did a performance audit and found that third-party ads comprised a whopping 50% of the calls to their pages. They were averaging 80 to 100 roundtrips per page because of the company that was serving the ads.
Solution: Think about speed when choosing your ad vendor.
When selecting a vendor, ask them how they optimize their ads to maximize performance. If they don’t have an answer for you, consider giving them a pass. (I know this isn’t always an option, and sometimes there are very good reasons to go with a company despite the performance of its content, but it’s worth keeping in mind.)
Problem #3: Badly optimized pages
I’ve talked before about how all browsers perform differently in terms of how they prioritize page elements, and about how loading elements in the wrong order can mean that your visitors’ eyeballs don’t land on the content you want them to notice. It’s worth repeating.
Solution: Prioritize page elements so that third-party content loads last, not first.
You need to look at how your key pages render across major browser types, identify which page elements are rendering first, and make sure those are the elements you most want your users to see. This might not always be possible – or desirable, if you rely on ad clicks – but it’s a strategy to bear in mind.
Whether you’re a developer designing third-party apps or a site owner who is choosing them, here are a few good links for further reading:
- HTTPWatch: Asynchronous Google Analytics is better but not faster even with IE 6 and 7
- dynaTrace blog: How to identify IE add-ons such as Skype that impact web site performance
- F5 DevCentral: Does this application make my browser look fat?
- Sergey Chernyshev: SLO-JS and how to speed up widgets [Added August 19, 2010]