I think a valid solution would be a combination of the two. Keep registration closed to invite only. As shown by the numerous keys posted in this thread alone and the ones being put on Twitter, this should allow for an exponential growth of the userbase. Also keep the delay between new account registration and the ability to generate keys. In addition to this, bring back the 50 post quarantine from the old forum. This will stem the tide of trolls and spamming attempts while at the same time generating an atmosphere in the other forums that encourages posts of real value. I think that a daily/hourly post limit should also be implemented here to stop new users from simply spamming the quarantine forum with one-word posts so they can make it to 50 as fast as they can type. Remove the functionality that allows for users to see who invited them. There is no purpose in this visibility and only serves to pose a potential security threat. DPR should be the only one able to view this information and a data retention policy should be put in place. The records should be purged either after X amount of days have passed or once the new user has reached 50 posts and is capable of generating keys themselves.