Pincus, appearing at Fortune Brainstorm Tech in Aspen, says that Zynga (ZNGA) games initially thrived on social networks like Facebook (FB), because “that’s where people were hanging out.” Now that so many consumers are spending more time on smart-phones — particularly in North America — Zynga needs to follow the crowd.

“Mobile is definitely earlier-stage [than web], but we’re encouraged because all of you are holding smartphones in your hands, half of you are playing games today and we can all do in-app purchases,” Pincus told the audience. “All of the components are there.”

Pincus added that he already believes Zynga is the largest mobile gaming network, even though he acknowledges that the market is “fragmented.”

A couple other notes from the Pincus interview:

* Real money gaming: Zynga is seriously exploring “real-money” games, which is otherwise known as online gambling (perhaps via Zynga Poker). Such things are currently legal in places like the UK, but still illegal in the U.S. Pincus did not reject the prospect of Zynga joining a lobbying effort to change U.S> law, but said he would hope to advocate for more “mass market consumer-oriented, and less toward hardcore style gambling.”

* DrawSomething: When asked if Zynga had overpaid for Draw Something maker OMGPOP, Pincus said that Zynga did not make the purchase to boost short-term financials. “It’s too early to tell after one quarter.”