PPC - Stands for Pay Per Click. Basically every time a user visits your web site and clicks on a advertisement link you make money from it. It is usually a couple cents per click which add up quickly if you have a large user base. The most popular is Google’s Adsense program, but they are very picky on the type of traffic you send.
Coreg - Coreg or Co-Registration, is becoming more popular. This is when you have a user sign up for your web site, but during the signup process you also give them a check box option to sign up for another web site as well. If the user agrees and checks the box you will receive compensation for it.
Use a combination of all of the above income streams for your web site. Depending on the type of site you want to run it is always good to have a general idea of how you are going to make money from it. Try to figure out how to make the most money without inconveniencing the user. Otherwise the user will feel bombarded with ads or too many offers, which can likely result in the user being put off of your site and not visiting it again.
