Letterman, who is almost 67, announced his departure on yesterday's program. He has been third in the ratings in the much coveted 18-49 age group behind the far younger Jimmy Fallon, who replaced Jay Leno on NBC's "The Tonight Show" less than two months ago, and Jimmy Kimmel of ABC. Since taking over, Fallon has built up a solid overall lead.
Candidates to replace Letterman include Stephen Colbert, a late-night host on Viacom's (VIA) Comedy Central, and possibly CBS's other late-night host, Craig Ferguson
In January-September, ad revenue at the "The Tonight Show" and "Late Show" fell 9% to around $100M each, while sales at Comedy Central's "Colbert Report" rose 12.8% and at Jon Stewart's "The Daily Show" 6.8%.