Has anyone used GREEN METROPOLIS to sell books?

[sushistar]

It looks like a good idea?
I've listed a couple, as it's free - do they actually sell though??

Green Metropolis

I've listed loads over the last 6 months but only sold one. Think others have more postive experiences though?

I have sold some, bought more than sold though.

I've got 6 listed on there, no buyers so far tho...
I suppose it does no harm since it's free!