For those who like to maintain that they did actually receive some form of education in their lives, why not run The Blog Readability Test over your blog? It analyses your blogging style, and then gives you a rating based on the quality of your vocabulary and grammar - at least, that's what one would rather assume it does, the tool doesn't explicitly to do that. It could be plucking numbers out of thin air as far as I could tell.
Anyway, if you're wondering whether your blogging style is more suited to MySpace and LiveJournal than to Wordpress or Blogspot, give it a go. For those who really like a bit of self-validation, you can then add an image link on your blog, although beware that the site does use the image for a bit of advertising as well.
Apparently I write at undergraduate level. I'm not too sure if I should be happy with that or not though.