When a group of people are talking and one person leaves for one reason or another. The conversation still continues and changes subject. When the person returns they still believe the conversation is on the previous topic and are confused for a moment.
Person 1: ...and then I totally sniped him from across the map. It was aweseome!!!
Person 2: brb gotta use the bathroom
Person 1: So I stopped playing right then because that was such a perfect kill.
Person 3: So do you wanna go see a movie tonight?
Person 1: Yea sure. What do you wanna see?
Person 2: Ok back. So what did you so after you sniped him?
Person 1: Whoa dude, you have some conversation lag going on, we already talked about that!