Actually, I don't have ten, but it's a nice number to project authority on a subject matter, which is why using lists and touting them in a blog post's title helps make the thing go viral. I guess people cannot digest paragraphs, or good ol' expository writing or–heaven help us!–essays anymore. They need lists, so they can have etch little compartments in their tiny little brains and also have food for fodder when trying to sound authoritative on a subject: "Yeah, there are three good reasons why…blah, blah, blah."
So my main (numbers one through ten) reason for generally shunning lists is this–you can't develop a logical argument or a good piece of exposition by hanging it all on lists. Oh, sure, you can squeeze in a list in lots of written pieces, but I'd say for the most part lists are mere shameless expositions of laziness (when it comes to writing) and hasty ploys to go viral for an audience that disdains having to read and be led to a logical conclusion.
When I read the following article on "blogging like the British," I kept trying to figure ways I could use lists on my restaurant review site, but nothing seemed to really fit the challenge. What am supposed to write, something that goes "the ten reasons I hate Jenny's Slop House are…"?
Anyway, the article has lots of good advice in it, but I would not agree that you have to spell out numbers through 100 (read: one hundred). I start using digits at 10, and that's a good enough artifice (most books might say to use digits after ten) for everyday writing.