To travel in time :) And also because I believe human knowledge is the sum of the past it can learn from. If information gets lost, it can't be part of that. It's the same beliefs that drive me to support open source & free software.
> what tools do you use?
I do a lot of data-mining as part of my day to day operations, in video games mainly. These are the main things I end up archiving, so I write my own tools.
On the flipside of this, thanks to archivists such as yourself, I've saved myself some time by developing a research perspective that first assumes ideas I've come up with may have been independently discovered in the past. This may be obvious to others, but for me it has been a game-changer for getting "to the meat" of problems, so to speak.
Largely, this mindset stems from a group of characters in the book "Anathem"[1] named the Lorites, characters who believe that all knowledge which can be learned has already been discovered, and recorded. While this is obviously fiction, and I disagree with the stance as an absolute, the idea that much of what can be discovered may already have been explored has saved me significant time; no longer do I find myself working on a problem only to find it has been studied and solved. Occasionally I'll find problems which have been studied, but not yet solved, and in these situations I'm pleased to have the fruit of others' data-gathering labors at my disposal as a result of the search caused by my initial assumption.
Archive.org! I upload everything. I organize best I can within my own disks/google drive (and sometimes public S3 buckets), but that stuff is too likely to go away within my lifetime to even begin to make a difference long term.
Recently added OCR to the process, which makes retrieval a joy.
I have no logical reason for doing this, it feels like a compulsion.
Why do you do it and what tools do you use?