You are right, spam is all over this website. I have personally just gone through the first page of each “Theme”, deleting posts and topics I consider to be spam. Trying to clear it all up, however, is not a job a couple of people can do without making this an obsession. As such, the best way to clear up all spam on this site is for legitimate users to report spam posts, and thus bring these spam posts to the attention of the admins.
This is what needs to happen; if users want to see an improvement in the level of spam, then the users themselves need to actually do something.
I hope that this will motivate any legitimate users to contribute to the combating of spam.