Okay, this spam is getting absurd, and there are multiple ways of doing this, and I going to post a logical one, but it does mean a bit more work for admins:
Another design forum I go to has instituted a rule were new members are in a "trial" group, they are in that for the length of their first 10 posts, and the post can't show up without moderator approval.
Normal members can give that approval, the admin/moderators can have a chosen few members that they trust to act as an human firewall... thus you can have more people letting through real people, thus if admin or moderator take a longer "holiday" there will always be someone letting new member trough, it also will slow down the waiting time for an new member (not like secretprojects, where you have to wait two months before the admin over there realizes this is an new member after you have almost spammed there mail account about how slow they are!!)