No. I don't have a blog because my perfectionism keeps me from even starting to write. I feel like if what I write isn't extraordinary, I have no business putting it out there at all.
This is basically EXACTLY how I feel. I sometimes think about starting a blog, to showcase things I've worked on, or interesting things I've read about, or new things I've learned, but I often think that it wouldn't be original enough to warrant doing. The thing is, you don't know until you try...
You should read Natalie Goldberg's Writing Down the Bones. She describes exercises to help get over these feelings, and gives you permission to suck. Or rather, convinces you to give yourself that permission.