Copious is a personalized social marketplace where people can buy and sell things to each other.

Like Pandora or Spotify, Copious gets smarter about you and your tastes the more you use it to browse the site, follow other users, “love” styles or clothes, and ultimately buy or sell some of those items.

“What we’ve built is like a combination of Etsy and Pinterest,” says co-founder Jonathan Ehrlich. “Etsy looks like a catalogue, and is the same for all. Pinterest stripped the discovery layer away from Etsy.

“Everyone’s Copius page is unique. What we want you to see is truly reflective of your passions and interests. We get most of our new users from person to person interaction. It makes us special and unique in this space. Personalization and social interaction are driving the business.”

The Copious home page does not display any products to a first-time visitor, but rather urges you to sign in with Facebook, Pinterest or Twitter (no anonymous users here) and begin the social shopping experience.

You are prompted to share a few of your interests around clothing and fashion (among about 15 options).

The site then presents you some people, many of whom are bloggers, who share your interests and are often good storytellers around those products.

“The third step is a personalized, curated experience tailored to you,” explains Ehrlich. “It includes actions you can take, such as buy, sell, and share with friends. It is always changing due to the actions of your connections, just like your Facebook page.”

The tie-in to the Facebook experience is not incidental. Ehrlich is the former head of marketing at the largest social network.

“At Facebook I was watching the transformation of top-down experiences to experiences organized around a people-centered system. Facebook is still the best example. Your experience there is powered by your friends, interests and passions.”

But Facebook was not built for shopping, and Ehrlich’s prior experience had been primarily in retail, including MobShop, a group-buying venture in the dot.com era.

“What we are trying to do with Copious is very hard and we have a long way to go," says Ehrlich. “But I'm fundamentally convinced that this is the future of ecommerce. The biggest trend today is around deals created within networks like Pinterest, Twitter, and Facebook. Brands and sellers want to know how to affix themselves to that kind of brand curation. These are immersive experiences -- personal, social, relevant powered by you.”

Although the early audience at Copious, which launched last year, was predominantly female, the company recently expanded to clothes and fashions for men.

Ultimately, Ehrlich envisions a marketplace that offers its users the ability to buy and sell anything.

“There is so much supply,” he notes. “There is $5 trillion worth of stuff sitting in our closets and garages. We are the most over-purchased country on earth. The challenge for every startup is getting demand. Liquidity and scale are the keys to success.”

I was curious just how closely Copious is tied to Facebook, in light of recent downturns at companies like Zynga that rely on Facebook for almost all of their revenue.

 “While Facebook is incredibly important to us,” Ehrlich told me, “we are like Pandora, Quora, Spotify, and Pinterest in that we all tie in to Facebook but are not shaped by Facebook.

“We have our own graph unique to every person. It is a stand-alone experience at Copious. Facebook doesn't shape the ever-changing ‘you’ on our platform.”

Copious makes money through a 9.5 percent fee on sales, although 3.5 percent of that is the standard pass-through credit card fee. Sellers can choose whether to add on the 6 percent escrow fee to buyers, or absorb it themselves.

The company’s staff of 17 is headquartered near the home of the World Champion San Francisco Giants.