It's a trope that most of us likely already know: Even the mightiest of heroes need a bit of R&R now and again. So upon wandering into town it's not unnatural that one of the first places they'll stop is bound to be the tavern. And here, they meet an interesting fellow (quite likely a drunkard) who babbles on incessantly about things he's seen and heard. Sure, much (if not most) of what he says is nonsense. But maybe, just maybe, he'll say something that's actually important for the hero to know!
My vision for this gameplay element is a modified version of the NPC scripts, that rather than point to one particular string which is then displayed, randomly chooses from a list of multiple predesignated ones so that the NPC says something different every time you talk to him. Bonus points if there's also a place to put in strings that he can't access until a certain part in the story, to make it seem as though he is commenting about plot related events!