you have to know it was a bitter divorce and you have to know that olbermann has long had a history of being a popmpous a** to put it mildly. olbermann would eventually confess he was very insecure and that's where this part of his personality came from. he has since apologized to former co-workers and written a mea culpa piece for salon magazine.
i'm not sure how this happened but a few years ago, dan asked keith (with espn's blessing, i reckon) to do an hour of his radio program every friday. well, obviously, it became so popular that olbermann was asked to contribute monday through friday. that's when those grumblings surfaced. whether or not, they were true is not known. but as part of their agreement to expand olbermann, he had to agree to never step foot on the bristol campus again.
hence, the reason olbermann does his part from a radio station in nyc.
hope that helps fill in a few blanks, webby!