senior member = totally cool dude
only joking!!! seriously i think this is largely a backend problem and i think the work going on in the background logging ips and analysing posts is really where any solution lies, ultimately combined with a judgment call from brett and the mods,
naturally if you consider it, if you were a serious professional spammer with a business model then to be in a trusted position in a successful board like this would be really valuable - so whats to stop someone putting enough effort in to become a moderator themselves, after all if its your job you could spend all day on the top boards so it wouldn't be difficult to do and like a good spy its easy enough to hand out "last weeks" information dressed up as informative posts.
it is a serious issue, i have no stats but i imagine the hits on and therefore influence of this site must be huge and why should my and all other contributors hard work by used by spammers as cheap product placement.
i realise i'm more ranting than adding anything positive to the discussion but any block on posting links would be severely detrimental to the board i think, as has already been said/suggested members reporting suspicious posts to the mods especially when they appear to be mirrors of others dropped on other boards, and we have to trust the admins/mods to make our decisions...
in court cases i'm all for the prosecution proving their case beyond reasonable doubt, but here i don't believe any legitamate member would be too upset if their post was squashed as a possible suspect - obviously i'd be a bit angry in the moment, but i'd quickly realise that it wasn't personal, i hope :), and accept that its for the long term good.