Twitter shares fell more than 10% in after-hours trading on Tuesday after the company posted weaker-than-expected revenue growth in the second quarter. 
Revenue for the quarter was 602 million dollars, an increase of 20% over the same period last year, the company said. 
But the company's revenue growth was less than analysts had expected, and shares fell as low as 16.31 in after-hours trading after closing the normal session at 18.45. 
Second quarter advertising revenue, the company's most important source of revenue, increased by 18%, to 535 million dollars, the company said. 
In the previous two quarters, advertising revenue had increased by 37 and 48%, respectively. 
Despite the reaction on Wall Street, Twitter chief executive Jack Dorsey said that the social media company had "made a lot of progress on our priorities this quarter".