I ask that question a lot. Probably my most useful tool.
You see, I don't learn much by myself. Most of the really important stuff I know I either read or am told. I even write blog posts reporting the results.
I really want to know the answer, as other people regularly tell me things that are better than what I heard.
Asking at the end of a meeting uncovers key themes, important details, and next steps which allow me to reconstruct the other details of the meeting.
Asking during a meeting keeps the discussion from bogging down and shows new directions.
Knowing I am going to be answering that question molds how I listen, which sharpens my understanding.
Once I was leaving a major meeting at Pax River with my technical partner, his boss, and my boss. I started the car and and my partner turns to the back seat and asks, “Well, what was the best thing you learned?”
The bosses were stopped, unprepared, had no idea, so one asked why he asked?
“Well, Dick always asks me when we get in the car.”
I hadn't known that. And I've remembered ever since.