It seems Mr. Extortionist was short on cash from a very nasty divorce. What better way to make a quick 2 million than to extort it from someone with $$$'s and some skeletons in the closet that he probably doesn't want his wife to know about because they probably happened while he was dating her...since it seems like Letterman dated his wife for like 9 or 10 years.
Also it seems that one of the staffers complaining of harrassment also happened to live with Mr. Extortionist for quite some time, but moved out like a week ago...this could get very interesting.