Most of the people underestimate the importance of alexa but this is the only one indepenadant tool ranking sites in internet. How you can use alexa?
Look here:
http://traffic.alexa.com/graph?u=bon...=freshpuss.com
boneme.com is 300k freshpuss.com is 10k (according the porngraph.com)
If you find a trader you can compare with your site (just change the domains in the above link).
If the site is not presented in alexa then it's under 15k daily.
if it's higher than 20 000 position then it's probably over 100k.
Now you can know if you can force this trader or not to start the trade at all.
The alexa result is not 100% reliable but you can trust it in 90% of the cases. You can check for your self.