Trading gift cards?

I remember last year hearing about a website where you could buy, sell, and trade gift cards. Anybody ever try one of those? Because as it stands, I have a $100 gift card to Anthropologie that I will NEVER USE and I'd hate to see it go to waste. At this point, I'm even willing to sell it at a discount, since I didn't buy it in the first place. Any recommendations? Can I do this eBay?