"...(It)never (happens) on non-Yahoo message boards. ..."
Further, most posts do not contain that which is copied from other websites, as the content is original. Part of what you say may be true, to some extent, since it usually is necessary to use tinyurl links, which are further disguised. However, many posts from others on this website post without the added effort of disguising links and using tinyurl's. This is proof of censorship for non-TOS reasons.