We constantly run into NPCs (non-playable characters) who have routines – they have places to be, things to do, and so on.
They have many different things they want to tell you as you’re walking by, and it’s not always related to what really needs to be done. It’s often funny or too stupid for the situation.
read more on Tubeblogger –Those silly Big-World games like Skyrim – Tubeblogger.
Nicko Gibson 
Well, not quite. If you know who to talk to then you may just gain a clue to what quest you need to complete. Anyways, they add spice to the online world. And a bit of population too.
Sorry your comment was in the spam box, don’t know why, I just noticed it (new to wordpress here).
Yeah they usually have something useful to say also, but if you notice the guards for example may keep saying “my cousins are out fighting dragons while I’m here on guard duty”, after they’ve already fought a dragon, or even while (the town) being attacked by one.
But in the full article I wrote more about things NPCs do rather than things they say. =D