I joined Facebook when it first started. I haven't got a huge social circle so my 'friends' number about 50 (almost all the female family members, including my 75 year old mother). Pathetic compared to the 1,500 'friends' my young niece has on her FB page - but then - that's a whole other issue . . .
I use FB mainly for storing holiday snaps, saving mine to 'albums' and looking at those of my 'friends' (again, mainly family!).
I go hot and cold over FB. I've closed it down a couple of times (once when a status update was misconstrued and another time because someone took exception to me ticking 'like'). I guess I was blown away by FB at the start, like everyone else, but it's becoming less and less useful to me. I realise this has probably got a lot to do with my age(I'm being practical here; I'm over 50).
I can see that for professional or pressure groups, it's developed to become something very useful. Although PGs certainly use it to greater effect (e.g.the UK street riots earlier this year, as a tool for incitement http://www.bbc.co.uk/news/uk-wales-15756260).
A member of our local CDG set up a group page, about 2 yrs ago, but, as with the majority of FB group pages that I've seen, the interest wears off after a while and people stop visiting.
I don't think FB is going to go away anyime soon though. It's rapidly developing and changing (often to the despair of members) but this proves that, if you want something badly enough, you will adapt.
I've been a member of Linked In for a couple of years too - but have never seen any benefit (again, this is probably to do with my age - there aren't many over 50 librarians who are headhunted - lol!).
I don't know about LISNPN or LATNetwork, so I'll have a look. Cilip Communities I have definately visited and I think I may have joined (?)I must re-visit!.
