@ Overgrow: well; one of the first step of the added action is to search for all users in group 4. Then it will compare each of them to all other users (including those in group 4, except the user itself... )
It should be easy to make this check complex, instead of m*(n-1) (m new members, n all users) something like n*(n-1).... But definetively I don't think php accessing mysql will accept such a high load and most probably you'll get a timeout error.
@ JDD:
- sorry for the mistake: loginlog.php comes from another my own hack and forgot to put that code into user.php. Hwr it simply calls the gethostbyaddr() php function against the given IP. ASAP I'll post the right code for that link.
- actually I think timeout problems couldn't be solved unless introducing a 'pagination' for the moderating members. I.e. for instance to select only 20-30 new users at once and then recycle. Till now I always completed my Admin homeworks day by day, so...

- in normalfont is printed the user under examination; in smallfont all the possible matches. Then in bold is highlighted the exact field which made positive the match.
Probably you could notice that on shortest words (or those with few alphabetics, the same for levensthein function...) you had many matches. I found that's is phisiologic for the php function's nature and tried to make some correction, but a minded-eye is the best one. This reason, all the matches are displayed and you have to decide (simply your are given all the informations to do that)
Bye