Sub Affiliate is an affiliate whom originally have been invited or recruited by Parent Affiliate and joined the Affiliate Program/Network "under" his parent account, therefore, sub affiliate is generating second tier sales commission for his parent. What is Tracking Pixel? Tracking Pixel is very important, it is given by the advertisers. We cannot track without tracking pixels. There are 2 types of tracking pixels. 1. Done by Advertisers. The merchants puts a tracking pixel on their thank you page that comes up after the order is placed. This sends the sale info to the network so it can be tracked. 2. Done by Affiliates/Publishers. Affiliates that do Pay-Per-Click (PPC) advertising sometimes want to track which keywords made sales. One way to do this is to get the network to place a tracking pixel for the affiliate. Some networks will do this and some won't. Very Important: Below is a list of the most common terms associated with the CPA industry..