A common application works well to make the process of applying easier, but my memory was the best schools used to add a supplemental question or two (although

A common application works well to make the process of applying easier, but my memory was the best schools used to add a supplemental question or two (although it's been a decade since I applied to college). Lower-ranked schools wouldn't add additional questions because they benefit from the increase in application flow by removing the friction of applying. YC doesn't have to do anything really. What will likely happen is that the common app each year will just be the questions YC asks or a subset of the questions YC asks (effectively giving YC the benefit of a supplemental set of questions). One other point. Unlike college admissions where you typically have to pay an application fee (and with incubators, a time cost associated with filling out disparate applications), it doesn't appear that there's any penalty for submitting your common application to every "incubator". There are probably some unintended consequences of every incubator seeing every application.