If you check my post: Conversion Pixels/Postbacks in Affiliate Marketing, you know that Conversion Pixels and Postbacks are the same thing – Checking the conversion.
Conversion Pixels and Postbacks can be generated from the affiliate tracking software like Prosper202 or CPVLab or something else. This kind of software will create unique numbers to each visitor who click or visit your CPA offers or landing page. We call this id as Sub ID.
Sub ID is most important in the affiliate marketing. Without a subID, conversions cannot be properly tracked in your affiliate tracking software. And you cannot find out which traffic source is good for your promotion.
Sub ID always includes with Conversion Pixels and Postbacks which insert into affiliate network system. If an offer converts, your affiliate network’s system sends the Sub ID of this visitor back to your tracking software through Conversion Pixels and Postbacks automatically. Then your affiliate tracking software will know that this visitors take an action (like sign up, purchasing, call, etc).
There is one different between Conversion Pixels and Postbacks. Conversion Pixels can’t send information back directly. They secretly send the converting user’s web browser to load a 1-pixel image from your server. This means that subid has already included (you don`t add any subid parameter).
So your tracking software knows that any time a user requests your “conversion pixel”. Sub ID information is ready to be sent out once the conversion pixel fires.
But there is one disadvantage of conversion pixel. If visitors turn off 3rd party cookies, conversion pixel will diminish the ability for your system to track properly. So you need to ask clearly with your affiliate manager when you use conversion pixel.