If a post is deleted or edited, it is inappropriate in some way. Either too much of the post is off topic, or in violation of a forum rule. Post deletion/editing is lenient compared to stacking up warnings. Besides, inappropriate material makes for an unwelcoming community. I can't speak for anyone else, but if I logged into a forum and all I saw was off topic rambling, pictures of over half naked people, insults, and obscenities everywhere, I wouldn't want to be a member of that community. Unless, of course, that is the kind of forum i was trying to join.