I apply the same test to pretty much everything I do online these days, and as a result, I maintain a dignified silence through most social media channels.

I whitewalled my Facebook a long time ago, don't 'like' any pages, and provide minimal personal information only to friends.

I don't use Twitter because I figure, even if I had an account purely to follow people, the individuals/organizations I follow could come back to haunt me. The same applies to YouTube, Pinterest, Tumblr, Foursquare, etc.