Facebook is taking swift action to address its teen user growth problem worrying investors

Mark Zuckerberg, chief executive officer and founder of Facebook Inc., speaks during a House Energy and Commerce Committee hearing in Washington, D.C., U.S., on Wednesday, April 11, 2018.
Andrew Harrer | Bloomberg | Getty Images

Facebook on Monday addressed perhaps the most pertinent business problem highlighted by the trove of internal documents released so far by the whistleblower Frances Haugen: that use among teenagers has been declining.