I have been using ChannelAdvisor for nearly two years now & when I was chosing which auction management system to use I knew about Marketworks but they were not in the same league – it was more aimed at lower volume sellers and how the dizzy heights I could see the company I am working for reaching.
Anyway ChannelAdvisor bought Marketworks – see their press release here
I had always assumed that there were more customers than that to make such a high GMV figure!