I’ve kept up a bit of running commentary on this blog about the purpose and development of Facebook, and online social networking more generally - and Facebook does indeed still seem to be the place to be, especially for keeping up with distant old friends or contacts.

There have been some intimations of its mortality, however: although it’s been said for some time that there are more Londoners on FB than there are of any other city, this number apparently recently suffered its first monthly fall. And my teenager-with-her-finger-on-the-pulse friend recently declared that she thought Facebook was past its peak.

From its still-burgeoning popularity with everyone from MPs to companies and other organisations, large and small, you might not get this impression - but then the moment when large numbers of such people start getting involved is probably also the moment when some of its core audience start losing interest in it. Having said that, people over 40 who actually use their own profile on FB (rather than have their secretary run it for them) are still relatively rare. I don’t think it’s going to go away - it is simply too useful (and for useful things as well, not only for ’sending’ weird drinks to other people, and ranking which of your acquaintances’ acquaintances are better looking, and other such FB staples), and it remains far easier and nicer to use than any of its competitors - but perhaps it has peaked.

But if Facebook is slowing up, then one networking site which seems to be speeding up at the moment is LinkedIn. This has been around for quite a long time, but among a few (different) groups of my friends the number of people on it really seems to have accelerated over the last few weeks.

LinkedIn is very different to Facebook - in many ways even its opposite. It is focussed on professional business and job networking - so where stereotypically Facebook has all those photos of you getting drunk with your friends while a student that you’d desperately want your boss not to see, profiles on LinkedIn instead use that strange language that people use when they’re trying to make themselves sound responsible and help them get a job. Think “I managed procurement, sales and personnel management for a customer-focussed retail operation”, rather than dishing out free drinks to your friends while getting plastered with them in the student bar.

It is also not nearly as easy to use as Facebook, although it has improved quite a bit recently.

I was initially a bit sceptical about how useful it was - but a friend who does freelance consulting work assures me that she has got work through it, and it clearly is helpful for job-finding. It seems to have (like a lot of social networking sites) fairly strong geographical concentrations - for example a lot of my friends in Scandinavia seem to be on it, proportionally far more than my London-based friends.

So maybe it’s the next big thing - though frankly I can’t see it ever scaling the heights of Facebook, while it remains both so much less easy and less fun to use. It’s a fickle thing, being the next big fashionable online phenomenon…