Great list! Funny..
Personally, I feel it’s getting to be too much of it. I’m going to ‘un-join’ G+, for starters. Instagram is only for the people who are iPhone owners. Pinterest is a fairly new service, that quickly has become immensely popular [most of all amongst women?!].
I’ve had my Twitter account since 2006 and I don’t feel that I can part with it. I use it as a news source. Most often I find news faster there than on CNN.