Zoompf, slicing and dicing performance

Consider the top 1,000 most popular sites as ranked by Alexa; what type of content do you think constitutes the majority of data sent from their servers to visitor's web browsers? If you answered "image" you'd be right (according to Zoompf image downloads make up 82.96% of outbound traffic).

But what, pray tell, do you think might be the second greatest traffic volume? Most people would assume it to be HTML but at 6.05% it is slightly beaten to second place by JavaScript at 6.52%.

These results appear in the document "2010 State of Web Performance", a report to be published by Zoompf on Monday, June 21. The report will cover the fastest and slowest sites, the top site issues in the industry today, a breakout by industry, and will highlight the performance and issues faced by the big online names such as Facebook, Amazon and eBay.

What this breakdown of the volumes of content types tells us is where to concentrate our efforts when it comes to optimization because optimization isn't just a good idea, it has a huge impact on a company's bottom line.

For example, a half second delay in load time results in a 20% drop in ad revenue source) while a tenth of a second delay in page load times causes a 1% drop in sales (source).

According a Forrester report commissioned by Akamai, "Two seconds is the new threshold in terms of an average online shopper's expectation for a web page to load, and 40 percent of shoppers will wait no more than three seconds before abandoning a retail or travel site."

In other words, consumers are an impatient and fickle bunch and be even fractionally slower than they demand and you'll be throwing away revenue. This is the problem that Zoompf addresses but Zoompf's Web Performance Optimizer (WPO) service is not just about analyzing Web site performance; it also includes grading problems found according to their severity and ease of fixing and advises on solutions. The company offers a free service that you can point at any Web site to create a performance report that looks for some 300 problems.

For example, a report for Zappos, the famed purveyor of fine shoes, resulted in a scan of 50 URLs and found a total of 171 issues.

The problems ranged from "Critical" (one page with "Broken HTTP Status Code" and one more with "Content Served Without HTTP Compression") through "High" (one page with "Adjacent Images" and another with "Combinable Image Map") to "Low" (six pages with "Uncacheable Response (iPhone)" and 37 with "Uncommon HTTP Headers"). Overall, Zoompf reckons that fixing all 171 issues would result in Zappos seeing a performance improvement in the range 14.829% to 22.310% (which are, admittedly, oddly accurate estimates).

Consider the "Uncacheable Response (iPhone)" issue: Zoompf advises "The iPhone is only able to cache web server responses whose uncompressed size is less than 15 Kilobytes. This response is greater than 20K. There is no easy way to make this response small enough to be cached by the iPhone. If this is an important resource that should be cached you should redesign the resource so it is small enough to be cached. Caching responses on the iPhone will reduce web server load and improve page load speeds for iPhone visitors."

Zoompf's paid-for service (pricing to be announced) provides an even greater level of detail by spidering the target site to a deeper level, executing a more comprehensive analysis, and running scheduled reports.

This enhanced analysis includes the same "Defect Report" as provided by the free service (but for the increased number of scanned pages) along with an "Optimization Matrix" showing what resources can be optimized in what way, and what the savings would be, a "Caching Matrix", showing which resources are being cached, for how long, and warning about which resources should have caching information, and a "Coverage Report" that shows what areas of the Web site were assessed so that future scans can be guided to specific areas.

The Zoompf Web Performance Optimizer service is compelling because even the free version delivers actionable, prescriptive advice while the paid-for service is the kind of analysis that any serious commercial site absolutely needs. I've already checked out a couple of my client's Web sites … I now have some interesting discussions to have with them because, boy, do they have some issues.

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Copyright © 2010 IDG Communications, Inc.

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