Basically, every time you visit a site that has a follow button, a “tweet this” button, or a hovercard, Twitter is recording your behavior. It is transparently

Basically, every time you visit a site that has a follow button, a “tweet this” button, or a hovercard, Twitter is recording your behavior. It is transparently watching your movements and storing them somewhere for later use. Of course. This is likely true for all social buttons, not just Twitter. I've never known a social site to throw away free user-related data.