Something interesting, that I've read on Slate - was that Imus hired one of his stage cronies to tell racist jokes - his name is Bernard McGuirk.
I believe it was in the fall of last year, when I caught a segment of "Imus In The Morning", where McGuirk did an imitation of New Orleans Mayor Ray Nagin, using an ignorant, stereotypical black accent.
I thought it was kind of tasteless(even though Mayor Nagin had made some rather dumb remarks, concerning Federal assistance during and after Hurricane Katrina), but it didn't warrant what Imus's show portrayed.
The guys on the set, including Imus, were going teehee-smirk, over McGuirk's rendition.
http://www.slate.com/id/2164055/
The pretense of spontaneity brought on by having sportscasters like Sid Rosenberg (kicked off the show for saying of Kylie Minogue's cancer diagnosis, "Ain't going to be so beautiful when the ##### got a bald head and one titty") or executive producer Bernard McGuirk (hired by Imus to do "######" jokes) banter in the background was just that, a pretense. When Imus went upscale, he knew he himself could no longer be the principal vehicle for his old brand of taboo-breaking humor, much of it centered on sexism and racism and homophobia, and still court the center-left audience attracted to a 10-minute gabfest with Doris Kearns Goodwin. Imus was the classic '80s brand, shrewdly repositioned for the more genteel '90s. He triangulated. He brought on juvenile white males to say things he could then pretend to deplore.