[wp-hackers] Unique permalinks vs. unique post slugs

[Eric Marden]

> Using category like that is an extremely poor choice for SEO, IMO, and
> it also makes your URLs confusing and inconsistent. I would recommend
> against using it unless you have no other choice (client wants it and
> you can't talk them out of it).

Personally, I use categories in my URLs, but only apply one category  
to a post. This way both the cat and the slug are unique for SEO  
purposes, and then use tags for all the other topics I want to apply  
to a post.

-e