RACHEL MARTIN, HOST:

Good morning. I'm Rachel Martin. A teacher in Kansas wanted to teach his third-graders how quickly information can spread, so he sent a tweet explaining his lesson and asking people to retweet so his class could track it. It was tweeted in Oklahoma in minutes, and the kids were amazed. By recess, New York; overnight, Malaysia, Japan, Kenya. The actor Eric Stonestreet retweeted. So did the political analyst Dana Perino. The lesson - yes, information travels fast. The real lesson - be careful what you tweet. It's MORNING EDITION. Transcript provided by NPR, Copyright NPR.