I have a question to ask about signature links. I have a friend who has a travel site and he posted some posts on a travel forum so he could use a signature link. I have read his posts and they were good and to the point and added some valuable info. Well the travel site banned him saying that he was only there to get a link back to his site. Yes he was but he was not spamming in any way and his info was useful. Why are sites like this? Were they afraid of the competition?