#twiiter
Finaly I come to an conclusion. ;)
If the internet would be a property with an house with rooms in it, then the social networks are this:
#Twiiter would be the garden around. (very public and the most peoble unknown for you),
#Facebook would the childroom (Foolish, walk around with selfmade custums often and everone is a friend)
#Google+ is the living room where you invite true friends and also guests but unknown peoble could only look there through the windows, if the curtain is not closed)
#Linkedin (or XING) is the workroom. (Most of the time no one there, the room is to be entered only for searching something )
#Diaspora is the private room (Save, closed, real names are not needed. A place to protect someone agiants cheasers)