Not only that but facebook may block your account at a whim. Happened to me once for posting 'explicit pictures'. The picture was not even explicit, apparently

Not only that but facebook may block your account at a whim. Happened to me once for posting 'explicit pictures'. The picture was not even explicit, apparently something tripped their automatic 'skin detection system'. But the result ? I couldn't log into any 'facebook connected' sites. Better to create separate accounts on each site and minimize dependencies. Also, if you lose your facebook password, it's just your facebook account that'll potentially get affected.