It is not allowed to start a thread asking for Facebook fans. It has no context and is considered self-promotional. We have a single long-running thread for people to post their Facebook page if they want to try and get fans, and adding your FB page in your signature line is of course allowed.
In this case, starting a thread adding a Facebook page in the original question is frowned upon as it could be viewed as a solicitation for fans instead of a real question.
You are allowed to post links as long as it's an answer to a question posted on the boards.