How could you be convinced to use a website that allows you to view and control all your email accounts along with your MySpace and Facebook and twitter all from one place?
I'm not quite sure what you mean. But Twitter and Facebook are two different things.Yes, I know you can post your tweets to Facebook, but I think thats as far as it will go.
This is call "website whitelist". Most internet filtering products have this kind of feature. If you prefer software solutions, I would recommend "WFilter Enterprise".