This is so true. I think the bulk of my consulting work comes to me via my blog - I've put basically no effort into seeking it out. A conversation which happens with some regularity:
Bossish person: "We are having trouble with $MATHY_STUFF. Do we know anyone who can help us with it?"
Codeish person: "I've been following these tutorials on chrisstucchio.com..."
I'll disagree with patrick a bit about "a visual identity distinct..." and formatting, at least for people who never touch the frontend. The people looking for you probably don't care that much.
Here are some fugly blogs of people you'd almost certainly hire:
http://www.johndcook.com/blog/2008/08/21/random-inequalities... http://www.stephendiehl.com/posts.html http://elem.com/~btilly/ab-testing-multiple-looks/part1-rigo...
That said, dropping $1000 on some pretty visual design probably can't hurt.