Facebook is the second most visited website in the UK: in June it accounted for 7.14% of all UK Internet visits and over half (54.48%) of all visits to a social networking websites. In terms of total visits it continues to trail Google UK (9.59% market share in June) and, as we’ve highlighted before, will continue to do so for the foreseeable future. However, using the measure of total page views rather than visits, Facebook is way ahead. As the table below illustrates, the social network accounted for 16.73% of UK page views during June. In other words: 1 in every 6 Internet pages viewed in the UK was a Facebook page.

Facebook continues to grow around the world (last month it reached half a billion registered users) and there is no doubt that it leads the social networking pack in the UK. However, with 26m British users already, when will it start to reach saturation point? As the chart below illustrates, Facebook’s market share of UK page views has trebled over the last five years, but growth has slowed significantly over the last six months. Last month there was a slight decline in share, but this may well be down to seasonality (the August / September back to school / college / university period is significant for Facebook).

Another metric is average time spend on the site, a key metric for user engagement on social networks. Facebook has a very high average session time (almost half an hour) but, as the chart below illustrates, this has also stabilised over the last six months after increasing rapidly during the site’s ascendency. Cleary Facebook is not losing traffic in the UK, but do these stats do point to a stabilisation? The rapid period of the site’s growth is now probably over in the UK, but does that mean Facebook has reached saturation point?

What next for Facebook in the UK? We’d welcome your comments either in the box below or via Twitter.