CEO Mark Zuckerberg sold shares this week to fund his and his wife's philanthropy.
David Einhorn bought shares of Micron, Hewlett Packard, and Altaba over the course of the last quarter.
Emarketer reports that Tencent, Alibaba and Baidu are chipping away at the US firms' dominance.
Cisco stock moved lower after hours, and traders will be watching the lower end of its price channel.
SunTrust Robinson Humphrey is urging investors to buy shares of Facebook, Amazon and Google.
Brands have been flocking to Instagram, shelling out $50 to $500,000 per sponsored post.
Facebook's Onavo app tells the social network what social media users are up to, and the data has been used to shape the company's product and acquisition strategy.
Tech stocks are acting less like high flying, volatile investments and more like safe havens.
While Instagram has more users, and may get to $10B, Snapchat users spend more time online and may reach $3B in three years, says Citi.
While Instagram has more users, and may get to $10B, Snapchat users spend more time online.