I had a pretty negative experience with Wikipedia as someone trying to learn something new. It's worth mentioning this happened around 1:00 am on a Sunday.
I have renewed faith in code reviews as a result.
Decided to stay up late learning algorithms like some caffeine-fueled hacker stereotype. I wanted to use Wikipedia to learn Quicksort. Choosing Wikipedia specifically because I had some crazy idea that it was going to be a great resource (foreshadowing). I think it was because I liked how they organized design patterns and algorithms in the footer.
The Wikipedia article was an absolute mess. The knucklehead who wrote it got the information factually wrong, and in a way that was so obtuse it was difficult to tell it was wrong.
The instructions were difficult to read, and the pseudocode was just terrible... And I don't mean "misinterpreted" or "matter of opinion". If you actually implemented it, the code doesn't work. And not just "unsorted" bad, but "returns 0" bad. I found 3 bugs. Those bugs were easy to spot, if you bothered to read the citation's source "Introduction to Algorithms". (p.146)
I wound up editing the page. I used to be an active Wikipedia editor, so I did it all 'properly' by the guidelines, even announced changes in the article's Talk page. After cleaning up the mess, I'm starting to feel like the one who bothered to read the rules to Monopoly.
I felt ashamed for trying to use Wikipedia to learn something new. That was the whole point. I wasted hours on an unreliable source of information and my attempt to correct it was not acknowledged or accepted. It was rolled-back within hours. Lesson learned.