I think it really comes down to the initial monetary investment of the idea guy. For the idea guy to approach a developer with a $200 software package and $8/mo web hosting they've got very little vested. Asking the developer to invest what amounts to anywhere from $60-$150/hr of development hours is unreasonable. Now if the idea guy has invested thousands into data, a nice piece of co-located hardware, exclusive partnerships with reputable advertisers, etc. we might have something. The idea is worth very little in terms of investment. I think the equity breakdown can be broken down as such: 5% for the idea and the dollar for dollar investment by each party.