In thing six, we're asked to compare and contrast some online networks: LinkedIn, Facebook, LISNPN, Librarians as Teachers on Spruz and CILIP Communities.
I can be found on all of these with the exception of LISNPN, the new professionals' network; I might set up LISOJC, the network for Old Jaded Cynical library and information professionals, as more suitable for people of my generation. If you're curious to see my profile on these services, the links below will take you there.
LinkedIn: I've been on LinkedIn since 17 May 2007, though I have to say I don't use it a great deal. The theory, as I understood it, was that lucrative contracts and job offers would come my way from my contacts. Apart from the obvious ethical objections to this, in fact it hasn't happened, at least yet. It has a very corporate feel, which doesn't really suit me.
Facebook: I've used Facebook since it was first opened up to users outside US universities; I tend to use it mostly for trivial, or social activity, and I find myself running the Facebook pages for my sailing and running clubs, Newhaven and Seaford Sailing Club and the Seaford Striders, as well as being a joint, not very active admin for Voices for the Library. When I worked in further education, it was a useful tool to reach students, but I can't say I've used it professionally to any great extent.
Librarians as Teachers [NB link goes to the homepage; it doesn't seem possible to link to my profile]: I came quite late to this group. The Spruz platform is clunky, but the network was useful when preparing for the Brighton LibTeachMeet in May. I can't say I visit that often.
CILIP Communities: I have to say I use these rarely these days, to the extent that I had forgotten my login details and had to request a reminder; I see I last commented on something in February. The Communities have always had a very 1990s bulletin board feel, and there are some petty annoyances, like the inab ility to control how my name is presented to the world. I tend to read the RSS feeds of topics, and stay away from the web version. That said, comments on the Visibility, value and volunteers post have taken off in the past twenty-four hours.
I have recently signed up to Google Plus, but have yet to use it in anger.

