Video is great. App/service looks solid. But marketplaces are so tough that I feel you almost HAVE TO START IN A NICHE and take the bowling pin strategy [1].
Look at Yardsale–they're a YC company and doing essentiall the same as Sold. I haven't seen much press about growth or follow-on funding.
Poshmark, on the other hand, is niche-focused (women's fashion) and seems to be growing well. Raised $15.5M. [2]