Tiburon, the FreeOnes board software automatically does that to links that are on what they consider to be competing sites. Essentially, trying to post them is a form of biting the hand that feeds us. You could probably evade the automatic check, but then a moderator would probably see it and have a worse reaction. Personally, whenever I've run into this kind of problem, I've just tried to find similar content to what I was attempting to link to on a different, non-FreeOnes-offending site.