Part of what makes social media "social" is that your identity is defined by you plus the community around you, so you've never really going to control your own identity.
Other people can't put things in your Twitter feed and if you want "real control" you can get a domain name and make a personal site. Even then there's nothing to stop somebody from saying you're a jackass on other web sites.
Thanks for the invite but I think I want to wait a little bit longer and see where they go.
I haven't used it, but it's YC funded I believe, and gets rave reviews: http://www.frid.ge/
1) Getting friends etc. to buy in. Until I do, I'm suffering from the ghost town problem.
2) There isn't a compelling use-case for me. Sure I'd like to get my family using it, except more and more of them are on Facebook and are fine using it. I don't have a compelling argument to get us to switch to Fridge (or some other smaller social network.)
I would try to get my workplace on it, but even then we're all friends on Facebook so what's the point?
I want to use it, I like it, I like the control it gives me, but I am struggling with the why and how.