I wrote an "article" and someone has threatened legal action if I don't remove it. Should I worry?

In order to sue you for libel or slander they must prove that you maliciously printed false information. Even if you wrote something that was untrue, you could prove that you were unaware that it was false and that you made an effort to investigate the truth. As for your umptions, as long as you state them as opinions then you are safe. The DJ is probably unaware of the law and just wanted the story removed. You should be very safe. Don't give in, protect the right of free press (not free speech other answers).