Is it a free website? Is it for playing online or for discussions/articles/news/whatever? If it appears to be in direct competition with chess.com your blog may suddenly disappear (get deleted by a moderator or the staff)
The rules are a little vague IMHO but unless you're trying to lure members away from chess.com or selling snake oil as a cancer cure, you're probably OK plugging (er, discussing) your website in one blog (chess.com doesn't like the same blog posted in several different forums, regardless of the topic)
You can always click on Help & Support at the bottom of the page and contact the staff directly with your question.
I have just build a website about chess.
So can I post a topic about my website here?
Is there any rule about advertising in this forum?