Every time I end up on wikipedia page for some math or CS term I just give up on reading and search for other source, any at all. I know it is supposed to be an encyclopedia, and I am sure definitions are technically correct but it just isn't what most people need.
I remember wikibooks project tried to bridge that gap but it never got popular enough. I guess it is just easier to compose short notes compared to writing full blown manual, and its much harder to split such work.