Availability is the key to the retailer’s move up the mobile performance ladder.
Katie Deatsch , Senior Editor
Barnes & Noble Inc. is doing something right with its mobile site as of late. Over the past two months, the retailer has been steadily moving up the Keynote Mobile Commerce Performance Index rankings.
This week it eased into the No. 5 position with its mobile commerce home page loading in 4.98 seconds and loading successfully more than 99% of the time.
“Over the month of June, the home page has trended from a fair 98.5% available up to an excellent 99.6% available,” says Ken Harker, mobile performance expert at Keynote Systems Inc. The Barnes & Noble home page is also loading faster. Over the last three weeks, the site loaded in less than five seconds on average, Harker says.
However, despite the improvements, there are still ways Barnes & Noble could further optimize mobile site performance.
For example, Harker says the retailer could reduce the number of page requests for very small images to make its m-commerce site load faster. A typical home page load for a first-time mobile visitor to Barnes & Noble’s m-commerce site includes 16 page requests for images smaller than 1000 bytes (or smaller than a kilobyte) each, Harker says. Most of these images are used for navigation icons, decorations or shadow effects. Loading very small images is inefficient, as each new page request incurs relatively significant network delays compared to the small number of bytes being requested, he says.
To speed home page load time, Barnes & Noble might want to consider using new features available in the HTML5 programming language for shadow effects, rounded corners, and other decorative elements which could help eliminate the need for separate images that require individual page requests, Harker says.
In other cases, the retailer could implement CSS Sprites—a mobile page building tool that packs multiple images into one page request to reduce the number of requests needed to render a page. This developer trick can speed mobile page load times, Harker says.
“Barnes & Noble is now one of the top-performing and most available sites on the index, but every second counts with user perception, and even the top-performing sites need to constantly look for ways to achieve faster page load times for their visitors,” Harker says.
Barnes & Noble did not immediately respond to a request to comment on its mobile commerce site design.
Office Depot topped the Keynote index with a load time of 2.45 seconds and a success rate of 99.72% for a score of 988. Sears Holdings Corp. came in second with a load time of 3.36 seconds and a success rate of 99.70% for a score of 950.
The average load time for all 30 retailers on the index was 7.16 seconds, the average success rate was 98.86% and the average score was 682.
Click here and then click on Keynote Mobile Commerce Performance Index Part 1 and Part 2 to see this week’s complete results for all 30 retailers on the index.
Keynote Systems measures 30 representative m-commerce sites exclusively for Internet Retailer. The sites include merchants in multiple categories and channels, and of multiple sizes, ranging from such giants as Amazon.com Inc., Sears Holdings Corp. and Walmart.com, to midsized retailers like Toolfetch.com LLC. Keynote tests the sites in the index every hour Monday through Sunday from 8 a.m. through midnight Eastern time, emulating three different smartphones on three different wireless networks: Apple Inc.’s iPhone 4 on AT&T, the HTC Evo on Sprint and the Droid X on Verizon. The HTC Evo and the Droid X run Google Inc.’s Android operating system. Keynote runs the tests in New York and San Francisco.
Keynote combines a site’s load time and success rate, equally weighted, into a single score. Given that both performance and availability are important, the score reflects the overall quality of the home page; a higher score indicates better performance. Scores also reflect how close sites are to each other in overall quality. The index average score is the midpoint among all the sites’ scores.