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.
A free software license is a software license which grants recipients extensive rights to modify and redistribute, which would otherwise be prohibited by copyright law. To qualify as a free software license, the license must grant the rights described in The Free Software Definition or one of the similar definitions based on this.