You could add referral bonus based on overall spending rather than just DIDs, and then developers of software such as Ekiga could integrate account registration and setup directly into the software (as they already do for Diamondcard).

Is there something stopping them from doing this already?

What would be their incentive now, if they don't get referral bonus for anything other than DID? (Maybe I missed where you do offer other bonuses.) If you also offered it for overall funds then they could benefit from encouraging users to use your service by including convenient setup directly in the software.

Thanks for your feedback, however our rates are so low we can't offer additional bonuses beyond what we are already offering at this time.

My personal opinion: There is nothing stopping software developers from integrating easier VoIP setup into their programs, and I bet that it would get them more of a user base if they did so, so that is a motivation that isn't just profit-based. I didn't realize Open Source Software developers needed a profit incentive to advance the features of their product

Edward

Thanks! I contacted Ekiga, and maybe at some point other softphone developers would also be interested.