I thought this might demonstrate what can happen - board owner in legal hassles over posts:
http://online.wsj.com/article_email/0,,SB112541909221726743-IJjfoNnlaZ4nJ6tZXqJaqaCm5,00.html
http://online.wsj.com/article_email/0,,SB112541909221726743-IJjfoNnlaZ4nJ6tZXqJaqaCm5,00.html