While there are many, many rules to writing, there are just a few simple rules about blogging. They are probably more my opinion than fact, but I believe it's a good start.
1- Don't quote someone without their permission or linking to their site and giving them credit. This is kind of a no brainer and it's really pretty much protocol for life.
2 - Don't turn a private conversation/debate/what-have-you into a public blog post. And certainly don't write that post hastily when you're all offended/upset/heated because you're only going to make yourself look bad. 'Nuff said about that.
3- If the topic you are writing about is your opinion, it should be clear to your readers. If it's a factual, informative post, try to link to some evidence/facts/data to substantiate it.
4- Be kind. Remember other writers are your friends. They will buy your books, they will host you during blog tours, they will spread the word - good or bad. And I think we'd all like to have people speaking kindly about us.
5- Reciprocate. I once heard it said that the amount of return you receive in blogging is directly related to the amount of your effort (or something alon those lines). So if you want people to read your blog, you must read theirs. (I'm probably the last person to preach this!)
So what blogging etiquette do you live by?