In order to make registration forms really powerful, conditional logic is needed.
From Kim Winter (INCH Conference):
We want to ask every registrant, "Have you ever been to the INCH Conference before?" Then if they say yes, "How many times?" and if they say no, "How did you hear about the INCH Conference?" with a drop down with options like, "Friend/family invited me, Social media, Radio, Internet, Church... Then if they choose friend, ask "Name of the person who invited you?"