Just more gossip, but the first thing that comes to mind whenever I think of @Mike_FTW is "Fuck You, Pay Me". Which in principle isn't bad, but ...
Dan is a professional and has my respect, where as Monteiro makes cheap vulgar jokes. I know which attitude I prefer to support.
UPDATE: Other explanations I'd also bet on (might as well hedge, right?): (1) Gruber wanted to be with his friends on the Mule network (2) 5by5 was getting a little crowded, and Gruber wanted the Talk Show to stick out a bit more.
I had always assumed it was free and easy advertisement for their apps, sites etc.
No idea how much, but I think it was David Smith of Developing Perspective that said a week of DF sponsorship was $7K and 5by5 $5K? Sure at least the latter must depend on the show. Plus I'm probably mixing things up. Episode 42?