Do law professors realize how much law students are relying on Wikipedia for summaries and insights into the cases we are assigning? In the old days, students spent a lot of money on commercial outlines, stuff like this. I've never looked at any of those books, not as a student and not as a teacher, though over the years, I've had many students ask me to recommend one.
Back when I was a law student — I graduated in 1981 — you wouldn't want the professor to know you were the sort of person who'd need or want to use a study guide, so it always surprised me that students would ask me, and I had no answer to the question other than to be careful: These things can be out of date, they may contain errors, and you can be wasting time on a lot of detail that I am not including and missing things that I will develop in class.
The best view of what will be on the exam is what we're talking about in class, which is based on the assigned readings, so why would you put time into reading some questionable alternative material instead of reading the casebook, taking notes on that book, paying attention in class, and condensing your reading and class notes into an outline that forces you to understand precisely those things that the exam will be about?
These days, from what I've heard, students have shifted to Wikipedia, which has lots of great entries for the cases that we read.
I love Wikipedia. I think it is one of the greatest things that has happened in the history of mankind. But you've got to know what it is and what it is not. Who is writing and tweaking those articles on important Supreme Court cases? They're quite well done, but that means they are done by lawyers, law students, and law academics. These contributors offset each other and enforce Wikipedia norms of neutrality, but, of course, law folk are expert at embedding political and policy preferences in seemingly neutral material. (That's what makes the cases so hard to read and understand.)
The first time a student in my class referred openly to Wikipedia, he quoted something that was a bit off. Perhaps it described a state constitutional law provision as banning racial discrimination when what it banned was using race as factor in affirmative action. It was something that needed better editing in Wikipedia.
It immediately occurred to me that a very efficient way to write an exam in this course would be to quote the Wikipedia entry on various cases and, for each, ask whether it is inaccurate. One could pick 10 statements about 10 cases — or 20 statements about 20 case — and ask the student to pick the 3 — or 5 or 6 — that you believe to be most inaccurate and explain why.
It's fine to use Wikipedia. I love it. But you've got to know what you are dealing with.