I moved this post to 'Forum Related Issues'.
You are probably getting e-mails because the poster (spammer) has posted into a topic that you probably took part in.
Hence you get an e-mail to say there was a reply.
You can turn the replies off in your profile settings, but of course you will not be notified of legitimate replies then.
If that is not what you are receiving then maybe you can give us some more information.
Unless each post is manually approved before it actually is allowed on the forum, I am guessing that there is not a lot that can be done to stop someone posting what ever they want here.
More often it is not even a real person posting, just a bot that seeks out forums and makes these annoying posts.
There are automatic processes in place to stop most of the spam posts, but there will always be some that get through.
Rest assure that there are 4 moderators, all in different time zones that pretty much monitor what is posted here 24 hours a day.
Plus users can report a post and an e-mail is sent to the moderators to prompt us to deal with it.
I see there were 3 adds posted in the last 2 hours that have already been removed by one of the other moderators by the time I got here.