Looks like it's using a strict definition for each URL. http://producthunt.co is different than http://www.producthunt.co.

Yeah, definitely seems like some things need to be worked out. I have found it useful for tracking blog posts, though.

A quick + easy way to get some stats on URLs

Pretty handy though I'm not sure how accurate it is. Says that Product Hunt has only been shared twice on twitter: http://cl.ly/image/2U0C2O1M0o0Z