In addition to the points already made.
Would be an idea for people who actually DO want to spam to have a place where this is acceptable for instance our site
http://www.spamboards.com 
Hehe, i just couldnt resist, sorry folks but it IS relevant to the conversation
But seriously, a lot of boards are now becoming less spam tolerant, i know on European Webmasters i have made the forums completely spam free and have actually directed people in the direction of the Spam Boards site above.
There are a few regular posters on the site but traffic is always a good thing, hence more is needed.
The one MAJOR problem that may be encountered though, if people were allowed to spam general resource boards would be that the overall affect of the usefullnes of the board itself may be come diluted resulting in fewer return visitors and posters thus driving the marketable value of the forum down lower.
Business is business regardless of whether its spam or not, there HAS to be a form of modicum.
Regards,
Lee