Having lived through both MSN is more private and personal, and the Twitter/Facebook/Instagram is more liberating and gregarious, but also can be pretty vicious too. The former probably, though I was never really a Myspace person.
MSN was cool, but the chats were just never ending. I could spend the whole evening/night chatting to the same person.
MySpace was an ugly abortion. Ugh those terribadly designed profiles. People have no tastes and shouldn't be allowed to edit profiles like that.