I've got a webpage that promotes my own click bank product. I rank highly for my keyword, but my link in the Google SERP has a "?hop=idname" appended onto it. It's not my ID. I didn't create the page that way. It's not on the file now. There's no redirect like that either in my htaccess file. (note: "idname" is NOT mine or anyone else's id)

I did a search for inurl:"?hop=idname" and it's on a bunch of other clickbank products. Did that guys affiliate link somehow outrank my original url? Did I get hacked somehow?

I now sell the product through Paypal, so I'm not sweating it..but why is it there and how did it get there?

Google just found your site through that guys hoplink and indexed it. With Google Webmaster Tools you can specify which paramaters (such as hoplink) to ignore for your site. The index wil update accordingly after a few weeks or so. The settings can be found under Site configuration -> URL parameters.