Some interesting tidbits from this Marketing Charts article:
"While Facebook’s appeal is weakening, Instagram’s is growing quickly. In fact, Instagram is now tied with Facebook as the second-most important social network among teens, at almost double its share of respondents (12%) from the year-earlier period."
"Nevertheless, the same Pew survey found that Twitter’s adoption rate among teens had grown by 50% in just one year. The Piper Jaffray study results also indicate that teens believe that Twitter impacts their purchases more than Facebook and Instagram."
Twitter Overtakes Facebook as Teens’ Most Important Social Network | Marketing Charts