I definitely agree with putting some sort of limitation on the amount of active threads allowed. But I think that if someone has multiple names, they should be able to have a max of 2 active threads at a time. One thread could be for their rarest name, and one thread could be for their shop.
If...
Huge vouch for Buringrsgold! I sold him a name for 100m. No MM used. I went first. We didn't even need to use MSN. Got right down to business as soon as he got access to a PC. Thanks!