I think I remember a time where LinkedIn was getting a bit of flack for their practice of "encouraging" new users to share their address books with them, which

I think I remember a time where LinkedIn was getting a bit of flack for their practice of "encouraging" new users to share their address books with them, which would mean that, at best, LinkedIn could create "ghost" accounts seeded with relationships and waiting to be claimed, and at worst, sending not-entirely-wanted emails pimping their service to one's entire address book.