The debate about whether or not young people are losing interest in Facebook has been going on for a while now. Some say it's a problem that the media invented, others say that teenagers are indeed jumping ship in favor of new, more hip services such as Instagram, Snapchat or Tumblr.

Yesterday, iStrategyLabs came out with a report that appears to prove Facebook's teenager exodus. According to iStrategy, which pulls its data from Facebook's social ad tool, the number of users aged 13-24 in the United States has declined by more than 6 million since January 2011. If the data is correct, Facebook's teenage user base in the U.S. shrank by an alarming 25 percent in the past three years, indicating that Facebook does indeed have trouble reaching young users.