The Custom URL Tracking add-on allows you to create a custom URL for your product and track how many times that particular link is viewed.
You'll find the Custom URLs options in the Advanced options of your products.
Once you enter your custom URL, you can then decide if you want the page to redirect to the original product URL (ex: http://elise.internal.ithemes.com/product/codex/) or to use the URL you created.
Once you've add your custom URLs and updated your plugin, you'll now be able to track the different URLs and the views each has received.
This shows in the Custom URLs section of your Advanced options for each product.