I store a lot of "I've read the solution for that problem somewhere while researching something else." I still can't recite the stdlib doc for any of the programming languages I work with. There's only so much stuff I can cram in my head and reference docs are fairly easy to look up.
Not necessarily; an encyclopedia isn't just an unconnected catalogue of facts--at least, it's not supposed to be. An encyclopedia article about a given subject is supposed to show the subject as a connected whole; it will contain facts, but will also contain important relationships between the facts, general principles, theories that explain the facts, etc. If you have that kind of knowledge of a subject, you don't have to memorize all its facts, because you can easily get to them from the facts you do have memorized via one of many interconnections.