ok first of all, unlike in the old days when spam was created by computers, the current trend is for manual [we guess at some poor sods sitting in call centre type places earning pennies for any clicks their spam creates], so easy for them to get through any registration protocols, whatever we do. If other fora you visit are not attracting them it is simply because either they dont have the member numbers to be worth it, or they haven't been found yet.
Before christmas the mods made an effort to check every registration via member ID, we were getting something like 20 spammers for every 1 genuine member and something like 50-60 registrations per day - you lot wont have noticed, but for about 10 days I think we got just 2 spam posts rtm'd, and they were from 'sleeper' accounts, accounts that had been registered several weeks earlier. This was effective, but was taking the work of at least 4 mods at any one time to keep on top of it, daily. Fine in the run up to christmas when we are all a bit more relaxed with work, more difficult to keep doing it day in day out every day of the year. Oh and if you think the spam posts are a pain, the latest fashion is to not post at all, they simply add a spam URL to their profile and never post, those are the ones you guys generally miss, but we are having to find.
So, we switched to admin approval on everything, but it didn't really help because unfortunately all 3 admin currently have incredibly mad work schedules [sods law it all happens at the same time of course] so genuine people were left waiting [because if they aren't approved instantly, we get messages] and Xen simply doesn't have a facility for any passing moderator to do this.
So, Marcel is looking at other options but other things on the forum take his time priority wise so it wont be instant and to be honest, from a forum POV, it actually averages about 6 or 7 spam threads created daily, which compared to the number of threads started is a very small percentage. We take them out and the system often takes out several other registered spammers at the same time, which is always a bonus. In the overall scheme of things, they aren't doing you any harm, so for now, just rtm, note reported, and move on, the next passing mod will get rid.