[miguelrochefort]

If they agreed that they would delete everything they know about you at your request, sure. But most of them don't, which means you can't do anything.

Companies should not be forced to implement ways to delete data about users. That's just silly.

Why do you want them to delete the data anyway? To me, it sounds silly and looks like some kind of censorship. Embrace transparency and live with the fact that what is public remains public.