Interesting. Where are you from?

EDIT: Oh, I could actually check your profile. Some people fill those out.

"Going on about <something>" is an idiom I've encountered in Texas and seems common throughout the Southeastern US as well. You can get the essential meaning by thinking of it as a shortening of "Going on at length about <something>" with strong implication of excessive length, though it can be (and often is) used to apply to whole discussions among multiple people.