Replying to Me1000, with hashes it would still be trivial to create a system that determines when a friend's signed up, and alerts you. That doesn't require a f

Replying to Me1000, with hashes it would still be trivial to create a system that determines when a friend's signed up, and alerts you. That doesn't require a full address book entry - or any contact details at all beyond an identifier. It's not like Path is actually notifying using any of the contact details it stores, which means it's either representative of wasteful coding on their side, or of something else going on.