While holiday shoppers resoundingly voted for the convenience of the mobile Web during the Thanksgiving holiday weekend, the surge in traffic is tasking retailers’ sites, with outages and slowdowns experienced by Best Buy, Neiman Marcus, Gamestop, J. Crew and others.

Retailers’ mobile sites are more data-heavy than last year but, for the most part, did not start experiencing a significant decline in performance until Cyber Monday. The results point to how shoppers are increasingly opting to shop wherever they are from rather than tackle traffic and crowds to shop at bricks-and-mortar stores during the holiday shopping season while, at the same time, retailers continue to struggle with how to provide the features and functionalities shoppers want without hampering performance.

“In our view, the mobile sites’ performance thus far can be considered very successful,” said Mehdi Daoudi, CEO of Catchpoint Systems.  “This year the sites are much heavier, and up until now performance hasn’t suffered.

“But now, on Cyber Monday, what you’re seeing is a degradation – in some cases due to third-party elements incorporated into sites, and in others where the sites’ infrastructure was the problem,” he said.

Advance preparartion
Mobile accounted for 52.1 percent of traffic to retail Web sites on Thanksgiving day, up 22 percent from last year, according to data from IBM Digital Analytics Benchmark. Going back to 2010, only 6.5 percent of traffic came from mobile.

Mobile sales grew at even faster pace, up 25.4 percent compared to last year, accounting for 32.3 percent of online sales.

The trend continued on Cyber Monday, with mobile accounting for 39.9 percent of all online traffic, up 28.4 percent, according to IBM. Mobile sales accounted for 23 percent of online sales, up 28.7 percent.

At the same time, in-store traffic dropped 5.6 percent on Black Friday, according to ShopperTrak, but was up 27.3 percent on Thanksgiving as more stores opted to open their doors on the holiday. Sales for the two days combined declined 0.5 percent, according to the company.

“The biggest winners so far this holiday season have been the retailers who were prepared for a huge surge in mobile traffic,” said David Jones, Web and mobile performance strategist at Dynatrace.

“We wouldn’t say that there was a failure across the board, however many retailers certainly are having problems due in large part to the high volume of mobile traffic this year,” he said. “Best Buy, Cabela’s, Foot Locker, Staples and others have struggled. Conversely, retailers like Sears, Costco, Saks Fifth Avenue have been consistently leading the way in mobile preparedness.

“Because the stakes are so high, the key to handling peak shopping periods really comes down to preparation ahead of time – we call it ‘Perform or Perish.’”

Mobile Web vs. apps
When it comes to holiday shopping, consumers have clearly voted for the convenience of the mobile Web over retailers’ applications.

In an analysis of 46 million page views from mobile devices on Skava’s clients’ mobile Web sites and apps, including Gap, Staples, Macy’s and Toys “R” Us, the company found that the mobile Web accounted for 97 percent of retail sales from mobile devices on Black Friday while apps accounted for just 3 percent.

However, many retailers struggled with the surge in mobile Web traffic.

For example, Best Buy took down its site during Black Friday, reportedly because of a spike in mobile traffic.

Other retailers that experienced slowdowns or outages include Staples, Neiman Marcus, Gamestop and J. Crew.

Fatter sites
According to an analysis by Catchpoint, overall the top 50 ecommerce and mobile sites this year are fatter – meaning larger amounts of data on the pages to download – and slower compared to last year.

The median Web page response times for mobile Web sites for the entire group was 2.954 seconds, compared to 1.879 seconds in 2013.

The top fastest mobile sites were Sears, WW Grainger, Office Depot, IKEA and Saks Direct.

“Moving forward, the same lesson applies as it does throughout the year: always stay as slim as possible – especially on mobile – proper capacity planning, and be aware of what third parties you’re hosting and their performance limitations,” Catchpoint Systems’ Mr. Daoudi said. “This is the only way to ensure that you’re as available and as fast as possible.”

Final Take
Chantal Tode is senior editor on Mobile Commerce Daily, New York