Akamai and Jupiter Research issued a press release last week stating that any amount of time over four seconds is considered an unacceptable delay in loading a page on a retail website. They cited several negative consequences of ignoring said advice:

The consequences for an online retailer whose site underperforms include diminished goodwill, negative brand perception, and, most important, significant loss in overall sales. Online shopper loyalty is contingent upon quick page loading, especially for high-spending shoppers and those with greater tenure. JupiterResearch recommends that retailers make every effort to keep page rendering to no longer than four seconds.

Naturally, you should take this with a grain of salt, as Akamai really wants to sell you their web content distribution services, but it’s still an interesting datapoint.

Along the same lines, Marissa Mayer of Google recently stated that taking an extra half-second to load a Google search results page caused a 20% drop in traffic and revenue from their users. Basically, Google did an experiment where they boosted the number of search results per page from 10 to 30, which resulted in a page rendering time of 0.9 seconds instead of 0.4 seconds.

I’d love to see more data from the A/B testing that Google did. I wonder if there is a sweet spot in between 10 and 30 results, although one could argue that it would ultimately be a waste since the value of search results tails off rapidly.

The big takeaway, of course, is that the performance of your application (web or otherwise) is critical to user satisfaction. Faster is better, but you already knew that, right?