Length is just a number

How long should a blog post be? Is there a rule on this? Often times I will read posts from people suggesting that blogs posts should be short, an easy read for the busy people reading them. Some bloggers keep their posts to something you can read without scrolling down on the page; sometimes I get relieved when I see this. However, some of the most interesting posts I've read (such as this one by Bane) are longer yet they grip me the whole time I read them.

This post by Kevin Muldoon gave me the hope that there are others out there who don't mind longer posts. What's your take on it? Do you think there is a general rule we should follow for the benefit of our readers? Do you think that as long as the writing is good it can be as long as we want? What is your general length goal when you write blog posts? Do you (as I do) get nervous when you find you have a lot to say, wondering if anyone will read it all? Do you (as I have done a few times before) just skim a long post instead of reading it?
photo: D Sharon Pruitt