Bristol has been through a lot for a young lady her age, and many teenage girls are interested in what she has to say.
Like what? That abstinence is "just not realistic at all", per Bristol. Or maybe, how to get your best friend to tell your parents that you're pregnant. She even sees the inherent contradiction in her actions: "I go around and I talk about abstinence, then I'm out here in my underwear".
Fact is, if it was anyone else she be criticized by the Palin Amen Chorus, and rightly so.