Twitter actually delivered robust financial numbers in revenues and earnings per share, beating analysts' estimates.
But when everyone saw the user growth - and a decline in the level of their engagement in timeline views (people looking at their tweet streams, basically) - shareholders headed for the exits.
It got worse an hour later on the conference call with analysts.
One analyst suggested that he didn't believe Twitter's growth could ever accelerate in the U.S. again.
Another suggested that users were trying Twitter and then rejecting it.
Twitter reported 241 million users, adding only 9 million more since the last quarter. Only 1 million users were added in the U.S.
CEO Dick Costolo was asked repeatedly what he was doing to turn the numbers around. At one point, one analyst (we didn't catch his name but will update this post later when the transcript comes out) hinted that he didn't believe it was possible for Twitter to reach 200 million American even over the course of a decade.
The analyst suggested that Costolo assume U.S. user growth had gone up by 3 million instead of the actual 1 million reported: "Even if you triple the current growth, it will take you 12 years to get to 200 million domestic users. Can you get there?"
Costolo replied: "We have a plan to make a broader audience to get Twitter to understand more broadly. We've seen success on preliminary steps on that, we believe the cumulative effect of changes we make over the course of the year ... will result in changing the slope of the growth curve. We have every confidence that will happen. What exactly the slope of that growth curve will look like and when it will occur we cannot guess at."
That's Twitter's problem - most growth curves in social media are viral or organic, and follow a predictable "hockey stick" pattern of fast growth followed by a plateau. Costolo now believes he can turn his plateau back into a hockey stick.
A second analyst then asked whether Costolo would reveal a longstanding mystery about Twitter that the company has repeatedly declined to address: "How many people come on the platform, try Twitter, and then leave? ... that seems to be the problem."
Costolo replied: "We're not going to speak specifically to any specific numbers of new user retention."
He explained that Twitter was aware that new users had difficulty figuring out the best ways to use Twitter, and the company was working on making it easier so that they "get it" instantly: "It's not just 'get it' in the first weeks or months on Twitter, it's 'get it' on the first day on Twitter ... so that's a focus."