I think the that it's a lot like real life... Peer pressure plays a big role in governing how people act in general. I personally see a lot more community governance on Google+ than I have seen on FB.

Unfortunately, the people promoting how to build fan pages are the very ones encouraging the behavior of posting on other's pages. Personally, I think there is a place for posting as a business, but that is when offering valuable info or content to another page that could be a customer. It really really looks unprofessional to post on a competitor's page.