Going to be a short post for today, and this is mostly going to be for the new GMs out there. The lesson I want to convey is the title of the post. Let the RP happen in your game. By that I don't mean to make opportunities for it to happen, but to actually - literally - let it happen when it is happening. Far too often I've seen GMs try to speed up an instance when multiple PCs were chatting to try and get things "back on track." Today, I want to talk about that.
Let It Happen
You want to let instances where multiple players are RPing happen because those instances are genuine in character exchanges. Through those chances your players are establishing both their characters and the characters' relationships with each other. This is a great thing to have in your game, and if you can pay attention to it you can get a lot of good stuff out of it. To put it simply, this RP is one of the big points of the game, and you should let it continue. Especially if the players are all having fun. Don't try to "wrap it up." Let it happen. Really, it can only help.
IC Conversations Only
This rule only applies for IC conversations though. If your players start chatting about their work, their day, a videogame they've been playing then it is time to keep things going. Be careful of, but don't necessarily stop, IC conversations about the same topics. Mostly a problem for "modern" games, but still something I've seen happen. The idea here is that you let RP happen as it is the point of the game, idle side OOC chatter is totally different.
The Other Players
The thing to keep in mind when letting this happen is your other players. If Bob and Sarah are going at it in conversation, leaving Michael, Jen, Taler, and Dave sitting their holding their hats, then you should do something for the other four. This doesn't necessarily have to stop Bob and Sarah, but move your attention to the idling players. If Bob and Sarah need you, they'll grab your attention. Give them the spot light for a few moments, then turn to whomever looks the most bored and ask "While this is happening, what are you doing?" and go with that. This is basic, but bears mentioning here. Shifting the GM's attention to someone else doesn't mean people have to stop RPing with each other.
PC <-> NPC Conversation
The one you have to be most careful with is PC/NPC conversations. Here there is RP, which is good, but the GM is one of the active people in the conversation which can be dangerous. If all the PCs are involved in the conversation then you're golden. It is a full group scene and you should have fun with it. If a few - or even just one - of the PCs are not part of the conversation, then don't be afraid to cut away on occasion and see what the other person wants to do. Take that time to figure out what the NPC wants in the conversation, or to give the PC a chance to come up with a witty line or three.
Lots of talented GMs seem to be reading this blog now, so I'll put the question to you. What else on this topic would you like to say to a new GM?