Social networks received more UK traffic than webmail services for the first time last month, according to Hitwise.
In October, the top 25 social network sites received 5.17% of all UK internet visits, compared to 4.98% for email services like Hotmail, Gmail and others.
The figures show that a growing number of UK web users are now choosing to communicate with friends and contacts through social networks' messaging services rather than email.
In general, younger web users prefer social networks to webmail, while older surfers spend more time on email.
Hitwise's Robin Goad compared visitor data for Facebook and Windows Live Mail and found that Facebook attracted more users from the 18-34 age group.