User growth rose 5% in the last quarter of 2017 and 3% in the third quarter.
Snap says its average cost per app install and average cost per swipe in the United States during Q1 were well under half of 2017 costs, and the number of advertisers actively spending on its self-serve ad platform grew 20x over the past year.
Shares of Snap, which went public at a $17 tag, were last down 18.7 percent at $11.49.
Revenue jumped 54% to $230.7 million, but came in below analysts' expectations.
Maybe it was the February redesign of Snap's social messaging network that put off users, advertisers and publishers.
"We are now focused on optimizing the redesign based on our ongoing experimentation and learning", Spiegel continued.
Worse, the company acknowledged that its app redesign had been bumpy.
But it ended up setting off an outcry among users. Executives plan to keep tweaking the design, which adds more uncertainty about how Snapchat will appeal to users while boosting ad sales.
On the plus side, Williamson said, "Snapchat loyalists are highly engaged, using the app multiple times per day".
Also fueling the selloff: Snap warned investors that a deacceleration of ad revenues was likely in the coming quarter before picking up again in the second half of the year. That's up from its 187 million users, but the growth rate is 2.13 percent, its lowest ever. Safe to presume that people who were avid Snapchatters had taken to Instagram's Stories feature. However, changes have soured some longtime users on the platform. "We think Snap is a "show me" stories to advertisers (and investors), and has to move fast to change the narrative, particularly given its cash burn levels".
Aaron Goldman, chief marketing officer of data science and marketing specialists 4C Insights, commented: "Today's earnings announcement isn't the only indicator of Snap's performance". "This is the first full quarter that the redesign has been out in the wild", said Cheddar's Alex Heath. "We are already starting to see early signs of stabilisation". The app will make it easier for creators and brands to manage their Snapchat content and advertise on the app.