In the Olden Dayes, students had to scribble down their lecture notes as fast as they could. If you missed what the professor was saying, too bad.
Beginning in the 70s, though, students began to record lectures on cassette. That made it easy for anyone to either transcribe the relevant points or to listen to the lecture again. (Not all professors allowed their classes to be recorded, but that’s besides the point.)
Today, it’s easier than ever to make an audio record of…well, anything. And this new tiny USB microphone from Blue makes things even easier. Details at Engadget.