First of all, only the anonymous Tells are anonymous. If you send anonymous Tells, you don't have to fear to be revealed at any point. However, in case of misuse of our services, we share data with the Law Enforcement to track the sender of an anonymous Tell down. We only provide this data if there is a legal basis. Our Community Guidelines show which behaviour we allow on our platform.
So, to conclude: Treat others on Tellonym as you want to be treated. You don't have to fear that you are going to be revealed unless you commit a crime on Tellonym (bullying is a crime). Only law enforcement agencies are able to track down a person that sent a Tell and only do so if somebody filed a police report or started a lawsuit.
External pages that claim to know who sent a Tell are completely fake. We do not work with external services that claim to know the senders of messages and are never going to do that. Anonymity is an important part of Tellonym and we know that. We know that you trust us and we won't let you down.