It's not very often that an episode of "20/20" can claim to be Friday night's winner in the 18-49 demographic, but thanks in part to Rihanna's exclusive interview ABC was able to achieve a 2.7 rating, the highest of the night. In terms of total viewers, the Diane Sawyer interview brought in slightly over 8 million viewers.
-http://www.examiner.com/x-11363-Dallas-TV-Examiner~y2009m11d7-Rihanna-interview-helps-ABC-achieve-ratings-win

Impressive!