Hello,

We offer sigs as a convenience to the community here on bitcointalk. Our affiliate program is designed to become a passive income source for affiliates over time, something a sig campaign cannot achieve. Residual affiliate links posted on social media, blogs, etc. are likely to keep attracting traffic for the affiliate, while a signature will change, and hence terminate additional income for the affiliate, once the sig campaign is over. The current system is more scalable for both the affiliate and for us.