Also Everything is a good research database.
The difference is that here, you're getting clues you won't get elsewhere.
To give you an example:
Together with a friend of mine I had to do an essay about "Go ask Alice". This is a book rather unknown in Germany. So no one had ever heard that it is known to be a fake ( like the other books by Beatrice Sparks ).
However, after we read the node about it in Everything and got to know about the "fake rumor" we were able do some further factual research on it and came to the conclusion it is, in fact, most likely fake.
My friends and I wanted to know what Fahrenheit's temperature scale is based on.
We browsed through all our books, not one of them (and we have a lot of 'em, believe me) could give us a clue.
Finally we found the info on Everything.
Recapitulating: I would say Everything isn't a by all means a facual correct encyclopedia but you get a lot of information you wouldn't get anywhere else (particulary not from ordinary or official sources). This gives you fodder for further research.