Oldversion.com and oldapps.com host old versions of many Windows and Mac programs. A recent example where this came in handy is this. Roboform's latest release no longer exports the full site URL. Roboform even changed the previous version so that it no longer has this feature either. If you want to migrate to LastPass, you need those URLs. So the old version of Roboform is what you need. Another example is PRTG - It used to be very simple to install and set up. The most recent version is much more powerful, but you have so much setup to do just to do some simple monitoring. Of course, be careful running older versions because there may be security concerns.