Some compare him to O'Reilly , except that Olbermann is to the left and O'Reilly is to the right .
In 2008 O'Reilly decided to avoid mentioning Olbermann 's name on the air , and once cut off a caller who mentioned Olbermann . O'Reilly has also led campaigns against MSNBC 's political coverage without ever specifically mentioning Olbermann .