enigma1 - 11:28 am on Apr 28, 2011 (gmt 0)
You must refer to the application you use. In my case, page titles and links are kept separately. What you have as a page title doesn't mean it represents the URL 100%. By default the link may get generated by the title and have the exact keywords in it but you can edit the link in case you need to modify it. Or if you change the title the link will stay as it was. In other words they're independent.
I use some approximation redirect mechanism so if there is ever a request for example.com/this-coo the code will pickup the closest or more popular link or whatever conditions I put in it, to find a similar link and then do a redirect. This has is pretty much the same effect with having an identifier.
The problem with identifiers is that they may detriment the url as when you start having multiple ids with products, categories, brands, articles, topics etc and you want to combine them into one link you need to have prefixes in place and the ids can be longer than the actual text. And there are database dependencies.
If say you delete a product the identifier won't be there so you need to hard-code some other url if you wanted a redirect to a specific page. In general with database management because of the identifier dependency you may have quite some overhead instead of using plain links.