I have noticed some are using no-spam accounts for email addresses. Using these for a forum sets the alarm, why use one of those for a 3rd party phpBB forum?
So, over the next few weeks I am going to delete accounts using them.
Deleting Spam E-mail accounts
Re: Deleting Spam E-mail accounts
Also in the new year am going to purge all non-posters, it will clear up some database space.