Whenever I get an old computer, I always take a quick look through the hard drive to try figuring out what it was used for.
Found an old PowerMac that belonged to a radio station(Had some pre-recorded radio jingles and some recording studio software)
Found a Mac Classic II that was used by a college student, who I assume eventually became a teacher of some sort(Had bunch of college type essays, and then newer documents were work rubriks and stuff like that)
If I see a copy of quickbooks installed or something, I'll delete the program and the files because I don't have any interest in looking through peoples tax stuff, same with saved aim passwords, internet history, and pictures(one exception I made, that radiostation mac had some pictures taken from a quicktake of the mac when it was setup and various other pictures from the station's buidling)