I have an informational site on glutathione supplements. I added a forum. The forum gets far more traffic than the informational content. But, a lot of the traffic seems to be spambots trying to post pornography. It is my policy to disapprove any topics containing or promoting adult content. This morning, I disapproved 248 topics in the moderated queue. Thats typical. (Thank goodness for the "mark all" check box!)
I use phpBB3 for the forum. If I put Adsense scripts in the page used for posting, or a Google tool bar, or an Alexa script and add some of the glutathione content or links to the content, maybe Google will think these people are interesting in glutathione rather than posting pictures of naked women. So could that improve the search engine rankings for my informational content? Any suggestions as to specifics of how to do this?
Short answer is no. Longer answer is maybe but definitely not suggested.
In essence that would be an attempt at blackhat optimizing for google, which once it's found your site is banned. Might help initially, although I'd surmise that there would be little, if any, improvements.
If I have a lot of traffic that has nothing to do with content that I want to promote, could that have a negative effect?
Early on, I set bot permissions on the forums to "no access" because I was allowing off-topic posts promoting different things, i.e., spammy stuff. Otherwise, search engine rankings were really being hurt.