Conversation so far:
What impact did the Jay Leno show have?
abandoning a history of airing quality dramas at that hour.
what dramas?
such as Hill Street Blues, St.
Elsewhere, and ER.
What the Jay Leno show successful?
TV Guide similarly listed the show as the biggest blunder in television history in its November 1, 2010 edition.
What network was the show on?
NBC.
Why was the show not well received?
the show competed with The Mentalist, CSI: Miami, CSI: NY, and Numb3rs, four of television's most popular series.

Question: What is an important fact regarding the impact?
Self-contained rewrite: What is an important fact regarding the impact of the Jay Leno Show?