If you are into black marketing than I ams sure you have heard of one of the most recent techniques called cookie stuffing. However if you are a white hatter then cookie stuffinf is basically stuffing ignorant internet surfers with cookies to afffiliates (generally to places such as ebay or amazon because those are the most likely places people are shopping online).
So the goal is to stuff as many users with cookies as possible and hope that they shop at one of the popular internet marketplaces such as amazon, ebay, or what ever affiliate your are cookie stuffing for. Cookie stuffing can be highly affective because it is basically like promoting an affiliate for free because you do not need to spend money to send them to an affiliate page you simply hide the cookie in a 1X1 pixel box on a web page or in an image.
However cookie stuffing does arrise a lot of controversey and put you at a high risk of being banned by your affiliate because you can run into complications of stealing affiliate commissions from hard working people who are paying for advertising. Most white hatters will say it is completely wrong, on the other hand die hard blackhatters will say go for it.
I will leave it up to you to decide if it is moral or not, howerver I will let you know that you can easily make an extra thousand dollars a month cookie stuffing in your spare time!