I’ve just been doing a little research around the extent of use of some social software applications, and came across a recent Hitwise competitive intelligence study, in which it is reported that MySpace.com has passed Yahoo! Mail to become the number one ranked website in the U.S. based on market share of visits. And, among Social Networking sites in June 2006, MySpace accounted for 79.9 percent of the total market share of visits.

Bill Tancer, general manager of Global Research at Hitwise, is reported as saying “The fact that MySpace was virtually unknown by the mainstream Internet users two years ago and now claims the top position, demonstrates how hyper-competitive the Internet really is.”

What’s really interesting is just how far ahead MySpace is! The following table shows the growth in market share of visits according to the Hitwise research:

What I’d be really interested to know is how this list of Web 2.0 applications was chosen – and why, for instance, isn’t YouTube or del.icio.us on the list? Did these rank lower than the ones shown here – surely not?