Stack Exchange
Somebody remind me why we are entrusting the world's repository of programming solutions to Stack Exchange? Having recently "programmed" a webapp in Python (ie copy and pasted a bunch of Stack Exchange answers until things worked) I am pretty frightened. The website's business model is not that strong, and it could disappear tomorrow. Then what?
Yes, the website content is released under a CC-BY-SA license. Who is mirroring this content? There are some gross adware websites that collect this data, but they are both gross and mostly useless, obscuring answers behind links. That's not sufficient.
The problem with Stack Exchange is that it is incredibly useful, and unlike Experts Exchange you don't feel ripped off when you use it. But it is a fiefdom like any other, and I am worried.
It's true that Stack Exchange has problems, and is becoming less useful over time. Many of the rockstar question-answerers that sniped the easy answers (and thus dissuaded mortals from answering questions and becoming engaged) have left, and it is not clear that they are being replaced. Some of the advice offered on the site is becoming downright mediocre. And the endless lists of fascinating, distracting questions from hobby Stack Exchange sites are really irritating when you are trying to focus on solving a programming problem. But there's no question that without Stack Exchange a lot of us would be in deep trouble, and it is not clear how to deal with this problem.
Update: Chris Frey noted that Stack Exchange data is being copied to archive.org here: https://archive.org/details/stackexchange . This is possible because the content of Stack Exchange is released under a CC-BY-SA license. However, since the source code of the Stack Exchange site is (as far as I know) proprietary, actually using this data to recreate Stack Exchange will nontrivial.