As a research mathematician, who knows the author (Ravi Vakil) personally -- This advice is for the audience, not the speaker. (There's lots of good advice out

As a research mathematician, who knows the author (Ravi Vakil) personally -- This advice is for the audience, not the speaker. (There's lots of good advice out there on how to give a talk, too!) If Ravi gave a seminar talk, and everyone listening wrote down their "three things", then I'm sure he would be delighted if everyone's note cards were different.