… many, many things can change and your URIs can and should stay the same. They only can if you think about how you design them.
Why bring it up now? I got an email from Jens Anders Bakke a couple weeks ago, in it he asked what “… we regular users can do about …” the fact that Macromedia Forums was recently moved (from http://webforums.macromedia.com/ to http://www.macromedia.com/support/forums/). He brought up the fact that alot of people link to the forums when discussing a bug or a problem and because of the move, none of those links that matter (ie: the links that actually point to something besides the forums homepage) work (I’ve done it myself in multiple places). In fact, Google can find about 7,400 links to webforums.macromedia.com. Some of those don’t work anymore. It’s a small thing, but seriously, how hard would it have been to add a couple lines of mod_write kung foo to your Apache conf?