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

[Otto]

On Tue, Dec 16, 2008 at 3:02 PM, scribu <scribu at gmail.com> wrote:
>> 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).
>
> Confusing? Maybe.
> Extremely poor choice for SEO? I highly doubt that. If you have descriptive
> categories, it's quite the opposite.

You are aware that parts of URLs are not actually treated as English
words by all major search engines, yesno? The readability of URLs
makes little or no difference in that respect.

> If that would be a poor choice for SEO, so would nested pages.

No, because nested pages can't cause multiple links containing
duplicate content. Using categories in URLs where you can have more
than one category can.

> Anyway, if someone gets to an URL that contains a non-existent category
> slug, wouldn't it make more sense to issue a 404, instead of serving the
> post that has the post slug? Would that check be too expensive?

That check would be quite expensive, actually, as it would require
that you verify every "part" of the permalink in a page request. As it
stands now, it merely figures out the most specific part (easy to do)
and looks for a matching result. One database hit instead of several.
No result = 404. No verification of anything needed.

-Otto