Announced Wednesday, the Series C round of financing, which brings the company’s total amount raised to more than $23 million, was led by Highland Capital Partners, with participation from current funders Trinity Ventures and Redpoint Ventures.

With the new funding, the company intends to invest in infrastructure and customer acquisition, so that it can scale and add new resale verticals, including teens, maternity and adults, CEO and co-founder James Reinhart told me.

“As more and more customers turn to the internet to buy clothing, so far no one has really cracked the code of how to buy used online,” he said.

The site initially launched as an online marketplace for parents to exchange used children’s clothing directly with each other. But earlier this year it decided to focus on more of a consignment model, which allows the company to control the inventory and improve the customer experience, CEO and co-founder James Reinhart said.

Through the site, parents can send the company outgrown clothing in “clean out” bags (which are mailed to families free of charge) and earn about 30 percent of each item’s resale value. They can also browse the online store and purchase vetted, “like-new” used clothing.

Currently, the company has one processing facility in California, which helps it add 3,000 to 5,000 new items to the site every day.  But its goal is to open new distribution and processing centers across the country, including in the Midwest and the South, so that it can add 25,000 new items to the platform each day by this time next year, Reinhart said.

Other sites, including BabyOutfitter and StorkBrokers also help parents recycle kids’ clothing, and even online marketplaces like OfferUp, HipSwap and Copious could enable people to buy and sell secondhand clothing. But Reinhart said thredUP is distinguished by the volume of items it processes, as well as by technology that enables it to evaluate and itemize inventory.

The company declined to share user numbers but said it adds 500 to 1,000 new customers each day and that 50 percent of customers return to use the site again.

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Thanks to the rise of online communities – and the declining economy – it’s never been easier for individuals and businesses trade unwanted and unused goods and spaces for things that they value. (Even cable network A&E seems to have picked up on a trend with its series “Barter Kings,” launched last month.)

“I believe that we are living through a collaborative revolution as significant as the industrial revolution,” said author and collaborative consumption guru Rachel Botsman, at the TEDGlobal conference in Edinburgh last week. “It is taking us back to the old market principles of sharing swapping, bartering.”

Driven by an interest in authenticity and community, she said people are gravitating to services like Airbnb, TaskRabbit and Liquidspace that let people more efficiently exchange goods and services.

To be fair, most collaborative consumption startups are not based on bartering, even if they employ the same principles of trust and reputation. But it seems like a growing number of recently launched companies do indeed rely on old-fashioned in-kind exchange or support a form of it on their platforms. Here are five new startups that are part of the nostalgic trend.

Bondsy
Inspired by founder Diego Zambrano’s own experience of needing to get rid of stuff when he moved from Brazil to the U.S. years ago, Bondsy connects people to share and exchange their things. The mobile app lets people take photos of their stuff and then send them out to social networking friends, who can simply interact with the images Instagram-style or make an offer for an exchange. What’s really interesting is at this point, Zambrano wants to build the community around non-financial transactions. So instead of offering a friend $50 for an old chair, you could offer to take them to dinner. Bondsy was one of the most recent startups to graduate from the NYC TechStars program, and when I met Zambrano, he told me that things should either be beautiful or useful to people. If not, there’s Bondsy. The app won’t be released until later this summer, but people can sign up for the launch here.

CasaHop
Launched last month by former Huffinngton Post CTO Paul Berry, the Airbnb-ish site lets people swap homes and apartments with friends for free. “Airbnb is more about making yourself a mini-landlord and finding a way to monetize your home. CasaHop is much more about communities and clubs and people exchanging and trading,” Berry told my colleague Ryan Kim. People can use the site for free but the company could make money by charging existing clubs and other communities to allow their members to exchange homes among themselves. Many college and university listservs already serve this function for members, so it makes plenty of sense for them to go after that opportunity.

Smallknot
The crowdfunding startup, which was also part of the recent NYC TechStars class, lets people invest in the businesses closest to their homes. But instead of forcing borrowers to repay lenders in cash, they can return the investment in kind, with special goods, perks or private parties (even an oil painting, in one case). The average loan size for Smallknot tends to be under $15,000, but they fund specific projects, such as a new oven for a local restaurant. The startup grew out of Greenville, S.C. but has launched a couple of pilots in Brooklyn, so far.

99dresses
Launched in March, the Y Combinator startup promises an “infinite closet of free clothes.” Through the online platform, users upload pictures of unwanted clothes, which others on the site can buy with virtual currency. If people don’t have enough “buttons,” they can purchase them for $1 but, in theory, someone could trade their way to a whole new closet. New York-based Refashioner employed a similar concept until its relaunch last week. Now, users can also buy and sell items. But the swapping philosophy is still alive and well in that users can use credit from sales to purchase other items on the site.

HipSwap
One of the several startups aiming to topple Craigslist and eBay as a new and improved peer-to-peer marketplace, HipSwap mostly gives users a platform for buying and selling secondhand and vintage goods. But the company, which launched its platform in March, said a large percentage of its users also use the platform to trade specific goods with each other. While the marketplace wasn’t build to be bartering network, HipSwap said it’s an open platform that people can use in the ways that are most convenient and safe for them.

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