That's why, for instance, there have already been dozens of Fallon webisodes and the show has its own blog. Fallon has also become one of the biggest celebrity Twitterers, with 178,764 people currently following his feed.
The question is, does that mean anything? Does signing up for Jimmy Fallon's Twitter feed mean you're actually interested in watching his show? Is it good publicity to remind people to watch? Or is it just a combintation of fandom and voyeurism that doesn't really connect to an "old fashioned" activity like turning on your TV at 12:35 AM?
Fallon's feed does provide a bit of insight into what his day is like. Today's he's twittered about everything from a sound check to getting a bottle of Johnny Walker from Carson Daly to the snow in NYC. And, yes, there are indeed several reminders to tune in or set DVRs.
Of course I've always suspected that the main goal of these types of multi-media extens are as much the publicity they generate as the actual customer engagement. A search for "Fallon twitter" on Google News generates 218 results. And, yes, even if I'm doing it in a meta manner, this is result 219. If reading this made you think about watching "Late Night" tonight, I guess that Twitter feed really did do some good.