How does xfire supposedly do it?

[SuicideCoder]

Hi, i don't have access to a game machine right now so i cant test it for myself, but i read that xfire allows you to instant message without alt+tabbing...like how a hack runs ontop of the game...but how does it do this with so many games,...is it exaclt how a hack does it or does it somehow patch into directx

i remember also reading that for best results with the in game imming, that directx9c shoud be installed...so maybe it does patch into directx memory.

any ideas? source?