BTW it is not only on forums, but on just about any bit of text on a web-page. Certain words will stand out as links. The usually appear with a differentr colour from the rest of the text and under-lined.
But on occasions you are catching legitimate posts. Last night I tried to respond to my own thread but I am told it is spam. I have been trying to deal with a problem for a while and when I get a useful answer I cannot respond.
Not having seen the spam I don't know your criteria for classifying somethging as spam. It would be helpful to know.
If I told you what the criteria are I would be telling the spammers too, so I'm not able to do that.
What I can say is that your post is more likely to fail if it contains a link to another site. Other than that I can't be of further help. We'll gradually lower the shields as the risk appears to subside.
We get lots of registrations every day. Not all of them are from people who want to post - thousands of them don't need to register at all, because they just browse the site and read the forum threads. We have no way of knowing who will post and who won't, and it just wouldn't be possible to monitor all of them.
We don't have the resources to run a monitoring system on posts from new users, it would delay posts going live on the forums, and defeat the whole purpose of having forums that can run more or less in real time.
We pick up spammers pretty quickly, and routinely delete their posts; it's worked well for a long time. The real problem arises when we get large numbers of posts in rapid succession from several sources - that's an orchestrated spam attack, and the only defence against it is some pretty strong filtering. We have that system in place pretty quickly when an attack starts, but unfortunately it catches a few genuine posts in the net as well.