Our service is not intended for users under 13, and we specify this in our privacy policy. If we do become aware that people under 13 are using our service, if that's brought to our attention, we will delete their accounts. We also provide resources for parents and teens. Those are linked to our privacy policy.
It's important for us to empower people to protect themselves on the service, and it's important for us to provide tools and features in Twitter itself that actually do that. Our resources talk a little bit about this. Some of those features are, as I mentioned, you can protect your Twitter account such that your tweets are not publicly visible. If you're concerned about who might view them, you protect your account and approve who gets to see them. You can also block other users of the service if you don't like what they say. I also just think that the nature of following other users...because it's unlike other services, you don't have to follow me just because I follow you, so people can follow and “unfollow” at will. So if you don't like what someone is saying, it's very simple—