Facebook, especially with younger people, is a corrupted brand. Youth do not want to go to facebook just because of the connotations behind it.
Kid's parents and relatives are on Facebook. They don't want their crazy liberal lives on display for their parents, aunts and uncles. As of now Facebook primarily serves as a messenger when one forgets or loses contact information.
In America, Facebook is uncool, Instagram is cool. Reminds me of the days Facebook was cool. Warning, my mom has an Instagram account.