The website had 14.35m UK unique users during April, which was up by an incredible 288.9% on the 3.69m users who used during the same period a year before.
The average time that each Facebook user spends on the site each month rose from 228 minutes in March to 258 minutes in April, which is the longest browsing time compared to and .
Facebook's page impressions per user also jumped from 463 to 520 in April.
However, Bebo, which has the second highest number of UK unique users out of the social networking sites, recorded the highest number of page impressions per user.
The teenage website rose from an average of 632 pages per user in March to 665 pages per user in April.
The site's unique users also rose 3.4% compared with March to 12.03m last month, which was a 40% growth from April 2007.
Bebo users spent an average of 248 minutes on the site during April, which was unchanged from the month before, but was down 23.5% from year on year.
MySpace's unique users continue to steadily decline. The site fell 1.4% from March to 8.47m unique users. This figure was down 14.3% from April 2007.
However, its page impressions rose from an average of 299 per user in March to an average of 328 per user last month.
MySpace users spent an average of 129 minutes on the site during the month of April.