Worth pointing out the article is based around American habits, but I'd expect it to hold true throughout the world. There's also some breakdown on the most popular US sites from mobiles, and the expected top sites (Google, MySpace and Facebook) take to the wings when Saturday comes, and the mobile user's thoughts turn to leisure. Perhaps surprisingly, the classified ad site Craigslist comes top at the weekends.
Of course, most Web surfing still happens via PC, but M:Metrics' research shows that when it occurs by way of mobile, much of it takes place on the weekend. The number of unique visitors to the mobile Web spikes on Saturdays, according to March figures compiled by M:Metrics. The number surged to 4.17 million on Saturdays, an 8% increase from Fridays and 4% more than on the next busiest day, Monday, according to the study, which tracked behavior by 1,861 U.S. smartphone owners.