Well we’re not getting consensus on this one.

At our dinner with the CEOs of TaskRabbit, Lyft, Nextdoor and Zaarly, I tried to argue that mobile has been a bigger enabler of the sharing economy than social. Maybe that’s just because the companies that I get the most excited about in this trend have to do with location and making services in the real world so much more seamless and easy.

For what it’s worth, Lyft’s John Zimmer somewhat agreed, saying that when Lyft (then Zimride) was only on Facebook, it didn’t have nearly the uptick that it got after its mobile ridesharing pivot.

But others at the table argued that trust– and your real world identity– matters so much more, and Facebook was the one that really enabled that for the first time. The consensus overruled me: Social was the enabler; mobile was the accelerator when it comes to sharing. But I maintain that it depends on the company in question.

Facebook actually dominated a lot of the conversation over the course of the evening. In the clip below, we discuss why Facebook has been the core identity system of so many of these sharing economy companies, but at the same time, why so many people and companies are uncomfortable with Facebook being the core identity system of the Web. Should it be some other independent third party?

Simply put: Does Facebook have too much power?

Ok, so if Facebook is so powerful, why hasn’t Facebook itself dominated the sharing economy? After all, classifieds have been tried a few times on the site. Bo Fishback of Zaarly gave one of the more compelling answers I’ve heard on this one to date.