GPL is interesting in that it has wildly varying degrees of influence depending on what kind of software is licensed. Lots of companies, for example, extract v

GPL is interesting in that it has wildly varying degrees of influence depending on what kind of software is licensed. Lots of companies, for example, extract value out of Linux without thinking much about the GPL. Because the "linking" bit never comes into play. On a smaller scale, GnuPG is similar, because the default interface is pipes and not a linked api.