Imagine browsing at your leisure through an extensive international fashion wardrobe and choosing exactly what you want. Swapping clothes is a huge step towards sustainable living. By sharing what we already have, we are cutting down our consumption massively and reduce our carbon footprint.

There are a few examples of businesses that allow consumers to buy, sell, rent and trade used clothing, including Closet Infinite. Providing a slightly different twist on the notion, however, is thredUP, which uses a Netflix-like model with prepaid envelopes to help users swap the clothes they don't wear for some they will.

By now focusing just on shirts, the service is free to join. Users begin by setting up a virtual closet to keep track of the clothes they'd like to exchange, describing brands, sizes, colors and patterns—no photos are required. Users also tell thredUP what they'd like to get in exchange, including the brands, sizes and styles they prefer.
Next, members purchase prepaid envelopes—a special offer currently has a package of three half-priced at USD 12.50. The service then looks for good matches in the virtual closets of other members to find items that might be suitable. It sends them one such item for each envelope they've purchased, along with an address to send one of their own items to.
The result, as the site puts it: "out with old-to-you, in with new-to-you." If the recipient of an item likes it, they simply keep it; otherwise, they list it as an item they'd like to trade. Members can assign each other "stylie" points as tokens of appreciation for particularly nice items received, and those are redeemable for free stuff on thredUP along with qualifying them for special promotions.

The Massachusetts-based company plans to expand beyond just shirts to include all clothing items, including kids' clothes. It also plans to sell targeted advertising and to begin offering premium services for better matching precision.