What makes a good blog posting?

I've been mulling this one over in my head: what makes a good blog posting? Here's my bullet point list, based on a mix of reading and browsing:

• Firstly, it should have a clear headline. None of this cryptic, punny rubbish - tell me what it's about. Now. Chances are I'm reading this in a list of headlines and I need to know if it's relevant.
• Secondly - and this is not a blanket rule - but it shouldn't be overlong. Note I don't say "short" - what I mean is it can go on for a while if it's a worthy analysis, but otherwise, don't keep us waiting with fluff.
  
• Thirdly: focus and relevance. Pick your subject and stick to it.
  
• Clarity.
  
• Transparency – link to everything you mention. And deep-link: that is, don't link to the homepage, link to the specific page that concerns what you're talking about.
  
• Knowledge - why would we read what you write, if you cant back it up?
  
• Finally, the best blog postings have personality – a passion about the subject and, if appropriate, a wit in talking about it.
  

Now, if you want to read someone else's opinion, The Washington Post give their tips here.