Look around and you see people putting up silos around social media. Invitation-only social networks like doostang.com and customized corporate vitual worlds are blossoming. FaceBook folks are putting digital ??oors?on their pages, controlling who can enter and for what purpose.

Is the golden age of truly open social networking in decline, as the young race to hide their youthful digital discretions and the rest of us tire of communicating with the masses and return to our own social/economic/political circles?

Yes, I know Twitter is very hot and runs counter to this trend. Yet, something is happening at the same time. Walls are going up. Something is cooking.

Thoughts?