Introducing .... WordPress Member Tracker Plugin ....
File : Personal Use Rights
Brief Note :
WordPress Member Tracker Plugin is a WordPress plugin that allows you to automatically pass the ' User ID " of each member inside your links.
The ID is passed as the "tracking code" of your link ( yout link must support tracking codes ), so once you get a sale, you know which member did it.
In the other words, this plugin allows you to know Which members Are buying Your or affiliate products that you recommend.