Temporary block for new accounts
It seems to happen that some guys get obsessed with someone on these sites and just make account after account harassing others. I suggest the implementation of a temporary block for accounts under one week old (or something like that). Maybe not a full block, but a limitation on wall posts and private messages, informing the new member with a message explaining the temporary limitation.
This option could be available as a toggle on a members profile if they wish to not be contacted by brand new accounts, or it could be a hidden option available only to admins that they can activate on an account in cases of harassment.
Current users who join the site now are restricted to how many status updates they are allowed to make for 72 hours.
Unpaying members are already limited to how many outgoing messages they are allowed to send.