From Chess.com rules
Basic Site Rules: http://www.chess.com/legal#rules :
Keep It Clean
You may not post any offensive content on Chess.com including your username, avatar, or personal description. You may not add any offensive comments, chat, or other content. The following behavior is prohibited and can result in your being kicked or banned: cheating, using offensive/vulgar language, using toilet humor, making personal attacks, spamming or advertising competitive websites, religious or political debate, intentionally pointless/distracting posts, and discussion of illegal activities (drugs, etc).