Last week I used Google's search data from the UK to look at the relative popularity of different social bookmarking services. The same can be done for social networks too, and here's what the data says:
Facebook dominates, as expected, though the tail off in search traffic in the UK in the last few months could become a significant trend. Stripping out Facebook, so that the fates of the other social networks becomes clearer we see how Bebo and MySpace are continuing to sharply decline on this measure. Twitter's growth may have stalled and LinkedIn is firmly bottom of the heap.
However, if we zoom in on just the LinkedIn data, there is a more promising picture for that service. It may be trying to serve a relatively narrow niche, but it looks to be growing quickly whilst doing that:
