I grew up in a small town and we (as adults) still remember and discuss when so and so did what. It's not so much the whole world will remember but those that go to school with you, live in your neighborhood, go to your church and the parents that know of the activity. People will use this against her as long as they know. On top of that, psychologically she'll believe the whole world knows about it when the rest of the world has moved on causing her to act out.
I feel you. Shit, people talk shit they think somebody did, that's life. Amber was going to have to live this down locally even if there was no video. Once she made this foolish decision, that was going to be a consequence. Her parents are going to have to put in some hard work to get her through this but this is the path she's on now. Get her off the computer, no FB, no twitter and let her fade into obscurity and it's over beyond her community. The fact that she's still tweeting and shit means no one has learned a fucking thing.