In general abuse is anything that is illegal under US law, causes a disruption of service or is otherwise disruptive to our ability to run the service. As far as our TOS goes, if we say it's abuse, it is. We will be very strict in our enforcement. We're hoping that backend procedures and processes we have in place will help us to profile abusers and prevent them from using the services as our goal is to prevent abuse while making the barrier to getting started as low as possible for legitimate users.

A tor bridge/relay might not be an issue but TOR exit nodes will almost certainly result in abuse complaints and action being taken.