Affiliates plugin

Hey i am working on a new site and would like to use the affiliates plugin i was told that it does not allow for link shareing on other sites, that for the plugin to work it would have to be a click from our site or within our sit. I want to be able to pay people when they sign someome up for our site cause we have free and paid memberships so when the get someone to sign up for a paid membership the get x% or $X. Do they have to have a site on our network. Can they promote oursite on their site with the link they get.