eBay obviously leads the pack, with Craigslist in second place, followed by iOffer and Etsy, then Edgeio sneaking in towards the bottom. The growth rate of Etsy is phenomenal, breaking the 10K rank in as little as 18 months. I was really stunned to see that Edgeio comes in last place and leveled off significantly compared to Etsy. Edgeio probably has the most buzz surrounding it, while I imagine Etsy caters to quite a vocal niche group (although, they might be a hard demographic because most people into Arts/Crafts aren't similarly interested in technology).
This was my guess as to how the chart would look, rank-wise: