What's your objective chatting during a race? I always figured it's a waste of energy... if I don't need to be efficient now, I want to save energy for later when I will. Sometimes I wonder whether people are trying to see how serious the competition is, doing calculations on the "too fast vs. too stupid" spectrum.
And Greylock's a nice race.
Yes, it's a bit of a gauge of how my competitors are doing. It's also just because it's nice to be friendly, and it makes the miles pass faster. Last year, having Debbie to run with up those stupid false hills made it much easier, because we were talking, albeit out of breath. I don't find it takes extra energy, and if it's a psychological boost, then it's worth it.
Greylock is a nice race, but the course beats you up a bit. All the loose rocks in the final 5 miles are rough.