I think legislation is soon needed to define a maximum time (e.g. one year) of storing a user's accumulated information unless he explicitly opts in for longer

I think legislation is soon needed to define a maximum time (e.g. one year) of storing a user's accumulated information unless he explicitly opts in for longer storage. I don't really care if Facebook personalizes ads based on my current interests, but eternally storing private data (and making it difficult or impossible to delete the older data) is a completely different issue.