launched Hiveinvite where you can easily create and send account creation-invites to friends.
Now there is an extra option for "open" invitations, for anyone to offer and of course to use
I'm starting with 5 to see how it's going...
Check claims
I plan to check each and every claim ie. is the twitter valid, is the reddit account okay? Does the owner of the twitter account know about hive?
That's a quick way to try to avoid bots in my opinion :)