A sticky for what is allowed and not allowed?

[kimanumanu]

I keep seeing some posts get deleted and having had one of mine suffer the same fate with no explanation, I think it would help all to have a sticky that clearly explains what is allowed and not allowed so that there is no confusion on the part of users. I have no problems with a post getting deleted if it is found to have violated laid down rules - however, the rules have to be easily accessible and a sticky would help in that.