On Wednesday afternoon, social giant Facebook (NASDAQ:FB) reported earnings and garnered mixed reactions from investors. On one hand, the mobile business continues to ramp extremely well. Mobile was 49% of ad revenue, or around $880 million in sales, while mobile users continue to rise. Any shred of doubt about Facebook's ability to monetize mobile can now officially be dismissed.

On the other hand, investor attention has turned to teen engagement as a proxy to whether or not Facebook's business is viable in the long-term; Facebook needs to stay relevant with future generations. On this front, the company acknowledged that it saw declining engagement among young teens, with fewer daily active users in this demographic. Additionally, Facebook implied it was hesitant to further increase its ad load in user News Feeds, which had helped drive the quarter's revenue gains in the first place.

In this segment of Tech Teardown, Erin Kennedy discusses Facebook's earnings with Jamal Carnette and Evan Niu, CFA.