As for the articles themselves, numbering your thoughts means you can't really write. Try it, you'll see that it is harder not to number them, but at least your text won't look like a schoolbook.
On the other hand, I see a disproportionate number of "Top X reasons"-like posts hitting digg and delicious/popular which leads me to believe that lists resonate well with readers. I'm not a blogger or link-baiter, but I'd prefer to write a mediocre article which is read thousands of times via prominence on social media sites versus a 'well-written' article with no numbers/lists that no one reads.
It seems like consumers of blogs and social media like lists, so bloggers logically satisfy that need.