Have seen where track bashing on racing forums (similar to this one - but NOT this one) hurt attendance at local tracks. Internet postings can be seen anywhere, and people who aren't regular attendees can be negatively influenced since they don't know who to believe but can see there's a bunch of idiotic drama. Usually the tracks that got hurt were ones with poor management - management that tried to fight its bashers in public on the forums rather than try to win those bashers back with kindness.
One of the worst cases is the current promoter of 311. First he got mad and said several unprofessional things on another forum and get himself banned from there. Later he realized he was still getting bashed there so he "made up" with the owners of that site and got allowed back on, only to start his stuff again and get himself banned again soon after. So he created his own forum to get back at the forum that banished him, but few people looked at it - and he started getting bashed on his own forum. So he closed it and started a Facebook page. But there he openly argues and curses anybody who disagrees with him even slightly, and now I understand he doesn't allow comments. The result? His car count has dwindled, with most of his regular drivers going to a competing track, and his grandstands are almost empty. I don't know how much more of his own ego he can afford.