I don't know why this is place in the affiliate section when they are ppc. I know that you could recruit someone and earn from their profits but I think this would still fall in the ppc section.
Chitika has an affiliate scheme. They offer 10% of earnings from new sign ups for the first 15 months...
Chancey when a company is offering 10% signup to anyone who brings in a new affiliates for the company it has an affiliate program in place...thats not ppc....i think it is right to place Chitika in this section