This website has been invaluable to me so many times. Basically it's a repository of outdated software that has been made unavailable by their original creators in an attempt to get you to get the later release.
I wholehearteldy agree with their slogan "Because newer isn't always better". I think to a certain degree newer versions of programs are useful when they provide better support, improved feautres [that people actually care about] and security and stability fixes, but too often in regards to commercial software it seems vendors just roll out new versions just to get their hands on more of our money.
Some examples of "outdated" software I still run:
- Windows 2000 Professional: the only version of Windows I'll touch)
- iTunes 5: I can't afford a video iPod, and it seems more stable than v6
- Office 97: Well, I use OpenOffice.org now, but before then I used it, even after 2000, XP and 2003 since came out. What other "useful" features did they include?