Snapchat has faced some skepticism from advertisers, especially after Instagram blatantly copied one of its main features. But it might have a new convincing argument: Its valuable young users can't be reached elsewhere.

Snapchat faithful: During the fourth quarter of last year, 35% of Snapchat's daily users in the U.S. don't check Facebook on that day, 46% can't be found on Instagram, and 61% aren't watching YouTube on a given day, according to data from mobile analytics company App Annie published by Bloomberg. During that quarter, Snapchat had 60 million daily active users in the U.S. and Canada.

Why it matters: Snapchat has faced a lot of criticism for not having as many users as Facebook, but this third-party report adds to its argument that its users are nevertheless incredibly valuable and engaged.