I know this isn't recruitment specific but I still thought it might be of interst. I got some stats through from Hitwise the other day about the top 10 websites in the UK ranked by market share of page views in September 2009.
They are
Facebook 14.5%
Google UK 5.8%
eBay UK 5.5%
YouTube 2.5%
Windows Live Mail 1.9%
Gmail 1.7%
Bebo 1.5%
Yahoo! UK & Ireland Mail 1.1%
Google 0.9%
Google UK Image Search 0.9%
In September Facebook was actually the second most visited website in the UK after Google UK (www.google.co.uk), but because users view a much larger number of pages per visit, Facebook was the clear leader in terms of page views. UK Internet visits to Facebook increased by 86.1% between September 2008 and September 2009, and have more than doubled over the last 14 months. During September, Facebook accounted for almost half (49.2%) of all UK internet visits to a social networking website.