But what about the rest of the time? Is Twitter just a forum, for hackers, trolls and the self-obsessed?
Over the weekend, Chipotle had its Twitter account taken over and filled with racist, hateful speech.
The hack was on Chipotle's end, not Twitter's, but it's just the latest example of a company getting embarrassed, via Twitter.
It wouldn't be too hard to imagine companies giving up on Twitter, deciding the risks outweigh the potential benefits.
And then there are the trolls. Those hateful little people who fill the comments with nastiness, and sometimes worse. A problem Costolo himself addressed when he reportedly said "we suck at dealing with abuse."
Those are the serious issues, but there's also this. The pop star Sia recently sent out a one word tweet to her one million followers. The one word: diarrhea.
It was retweeted 6,700 times.
Is that what Twitter has become?