Is there blogging etiquette?

And if there is, who made the rules? I just read my blog and found, much to my delight, comments on several of the entries. It was great. I want to say thank you, and I certainly now will comment more often because I know how it feels to be acknowledged on some level. But it would be interesting and fun to find or formulate an etiquette. What a better place to explore or implement this service than in a class devoted to the study of blogging.