Twitter swarm thins out

Twitter said on Friday monthly users dropped by 1 million in the second quarter, and it predicted that number would decline further as the company continues to fight against spam, fake accounts and malicious rhetoric on its social network. The shares plunged as much as 20% in early trading on the NYSE.

Monthly active users were 335 million — a decline from 336 million in the first quarter, San Franciscobased Twitter said. Though up 2.8% from a year earlier, it expects monthly visitors to fall again.

Twitter blamed the projected drop on intensified efforts to clean up the platform, stricter privacy rules in Europe and changes to the way its service is used through SMS messaging.