There are many social networks in many counties. Most people only know a few and probably use even less of them I personally use Hyves, Netlog and Facebook.. mostly for professional/development purpose (especially the first two).

But who is winning the social network battle? What network will we be on in 10 or even fewer years?

I think it has been clear for some time.. but checkout the nice World Map of Social Networks. If this were Risk who do you think is winning?