One thing that I'd argue about is that with many many topics on Wikipedia, you can start at the top, and via hyperlinks, more or less piece together a pretty good understanding of the topic. With the CS and mathematics ones? Not so much. It's just dense layer upon dense layer of very raw mathematics.

There's an ongoing argument over why certain editors seem to want to constrain and duplicate the constraints of physical encyclopedias in a near infinite digital medium. But I do have to agree that tutorials and step-by-step instructions probably don't belong there.

But I'll be honest, when I have to look something like this up, I usually just go back to my old textbooks vs. wikipedia since the explanations are usually better presented. The section on big-O in WP is one of the better ones, but I'll be damned if I can figure out the walls of equations in some of the other articles. Most of the material doesn't appear in any textbook I've ever seen (perhaps that's saying something about the quality of the textbooks I used way back in College?)