I had a few sales at Art.com with four images, last one in 2007.

When they started ArtistRising.com, none of the new uploads ever sold anything. As you can not upload directly to Art.com anymore, but to AR, I think this is a waste of time, unless you want to market images yourself. I believe Imageking, Redbubble and Fine Art America are better choices.
Also, I never manage to find any of my images in their search, but maybe it's my fault.
We had a thread about this once:
http://www.microstockgroup.com/general-stock-discussion/art-com-artist-rising/