Facebook Inc.'s (FB) shares hit a new low Friday as the company continued to struggle to convince investors it can leverage its immense popularity, especially on mobile devices, into stronger revenue and profits.

In its first quarterly update as a publicly traded company, Facebook reported its slowest revenue growth in at least a year, a tripling of its costs and expenses and a decline in some levels of user activity. Also, the company offered few specifics on future results and how it plans to profit from users spending more time on mobile devices, a trend that has threatened the social-network company's profitability.

"The lack of guidance and the well-publicized shift to mobile is weighing" on Facebook shares Friday, Oppenheimer analyst Jason Helfstein said. "Additionally, the company provided commentary suggesting higher [third-quarter] expenses."

For its part, Facebook said it remains confident in its prospects, especially on mobile devices.