PayPerPost (PPP) is a website which helps content creators such as bloggers find advertisers willing to sponsor specific content. The advertisers create opportunities ("opps") that describe the content they are looking for (e.g. feedback, reviews, buzz, creative, video). The bloggers (sometimes referred to as "Posties") then choose opportunities in their area of interest.
An open source license is a copyright license for computer software that allows the source code to be freely, that is by anyone for any purpose, used, modified and shared. This allows end users to review and modify the source code for their own customization, curiosity or troubleshooting needs.