How important is UI/UX web design to a blog?

http://www.paulgraham.com/

Maybe if it's a blog targeting designers. Otherwise, I doubt it matters much.

That said, design is part of branding, and branding can be quite important in some situations. I thought about it a lot in the early days of IH. I used design to make it feel more like a movement and a community, and less like it was just a blog.