In fact, he displayed a slide, which defined the cost of delays in stark terms, especially if you ran an ecommerce site. The slide, using data from Kissmetrics, stated that just one second in delay could result in a 7 percent reduction in conversion.
Wentworth kindly did the math here and assuming he’s accurate, if you’re an ecommerce site making $100,000 a day, a one second delay could cost $2.5 million every year.
Wentworth was speaking about the value of mobile design and putting mobile first. He made the point that mobile sites when well designed, are lean and mean, and only offer the most crucial information.
He used the United Airlines web site and mobile web site to contrast the differences. With the the regular web site, there was tons of extraneous stuff such as an ad for the United Airlines credit card and other promotions along with a reservation form (which is probably all you want).
When you compared this to the mobile site, it was task driven: book a flight, check in, and so forth. The mobile site was designed not only to get you in and out quickly, it was designed for speed because people didn’t have time to move around the site looking for the right function on a mobile device.
Wentworth argued that the task-driven approach might be one that web designers want to consider across platforms. Whether you agree with that or not, he pointed out that there was cost associated with this extraneous content, and that involved the time to display it.
As I wrote last August in, Every Second Counts on the Web, you need to be thinking about this because even short delays cause people to move on:
When visitors come to your web site, how fast your page loads has to matter. It’s reasonable to assume that the slower it loads, the more likely you are to loose your attention-deficit visitors as they drift on to the next shiny thing that catches their attention.
If the delays indeed cost as much as he suggests based on the Kissmetrics data, then he may be onto something. If you’re running and eCommerce site during this busy holiday season, you may want to consider the impact the site’s design is having on your bottom line because it could be substantial if that design is resulting in delayed load times.