Nate K writes:
Chris,
I previously wrote about this topic as well. I consider myself very particular when it comes to URL structure. I want to be able to accommodate friendly and descriptive links - but I also want to keep them short and to the point (easy to repeat to a friend). This is why I usually allow several different structures for my URL - but make the URL friendly link the main link. My new site will house this structure better than other sites I have done.
Personally, I don't think it is any slower because I index the post slug (unique key) in the database. If you build your database structure accordingly then it will still be quick to respond.
I work for a book publisher and I use multiple URLs in several ways. I want our books to have a friendly url, but I also want our bookstores and customers to be able to find a book by an ISBN. So, I have both URLs available to them, they can type in http://www.barbourbooks.com/book/detail/{ISBN}/ which will then apply a 301 redirect to the SEF url. Having one central location is key to maintaining a nice index (as well as avoiding looking to serve up duplicate content on 2 urls). This just gives your visitors multiple doors into your website - short and sweet URLs.
I think the key is to have the proper database structure, map out the possible doors to the website, decide on a 'main' page that will be the end landing page, and then understand your HTTP codes to send the proper code with the proper request (301, 302, etc).
Lesezeichen