Janine from Reflections from a Redhead has a fantastic post on this topic, so it seems pointless in repeating it. I added a few comments so I'll include those in the list as well as a few extras.
1. Let your readers know if they can expect your blog to be sporadic. I just get disappointed when I don't see any new posts from my favourite bloggers for a while. I'm not implying they should become enslaved to blogging, but it's just polite to let your readers know if you'll be disappearing indefinitely.
2. No amount of inviting (read: hassling) will make me want to 'follow' your blog. The more you annoy me, the more I will think you are an egotistical twat, especially if you never contribute any meaningful comments to my blog. When I became a blogger, I thought everyone was free to read any blog they stumbled across (it IS on the internet after all) - why do you need an 'invite'? Personally, I think the 'following' widget was designed to inflate bloggers' self-importance. Yes, I do have the widget...and I have 10 followers. Yes, 10. Nothing to boast about there.
3. I've read a few posts where the blogger has said, "I'm too busy to comment on other people's blogs." Really? But you seem to have plenty of time to put into your own blog (judging by the frequency and length of posts). If you want comments, then you must also be prepared to contribute to others' conversations...not necessarily the same bloggers who comment on yours, but SOMEONE. Give AND receive...or don't blog.
4. Don't make it too difficult for other bloggers to quote you. I've read a number of blogs where they ask that anyone wishing to use their content ask for permission first. If they are acknowledging you as the author and linking to your blog as the source, why do they need to ask permission? I don't want someone stealing my photos and ideas, but as long as they acknowledge me as the source, that's fine. I always thought blogging was a bit like referencing a source for a uni assignment. You don't have to ask the author for permission, but you must include the item in your reference list and reference any direct quotes.
5. If you want to write something controversial as a comment - PUT YOUR NAME. It is rude and cowardly otherwise. Be prepared to own and take responsibility for what you say - or don't say it.
Bloggers, listen up and hear,
How to thrive in the blogosphere.
Respecting each other is the way,
Be polite in what you have to say.
Own your comments, put your name,
Being anonymous is just lame.
That's a real person behind the screen,
Treat them if they're one you've seen.
After reading my list and Janine's list, what else do you think should be considered as blogging etiquette?