i have a vbulletin software licence and wish to set up a forum later next month. I want referals to be encouraged big time, but i wish to know. What does vbulletin do about stopping people refering themselves sercretly through another e-mail address?

I have no vbulletin software ,
I like Discuz! board

Could you only post if you have something useful to me

you can use Hack.
I think vbulletin should have this hack