NEW YORK – Keith Olbermann, MSNBC's most successful and controversial personality for his outspoken liberal prime-time program, gave an abrupt goodbye to viewers and said Friday was his last show.

It was not immediately known if he quit or was fired. Olbermann did not address the question, and MSNBC said only that they and Olbermann had ended their contract. He signed a four-year contract two years ago.