I have a website that gives freebies (=$$$) to new signups, so allowing throwaway accounts makes people do things like sign up for 100 accounts. Not giving fre

I have a website that gives freebies (=$$$) to new signups, so allowing throwaway accounts makes people do things like sign up for 100 accounts. Not giving freebies is of course an option, but then there is goodwill lost on that end instead. It sucks both ways. At least I don't spam my users, but they of course only trust that assertion so far and I certainly don't blame them - there seems to have been a significant rise in email marketing in the last 6+ months - probably some annoying YC startup or two making it much too easy for sites I signed up for at some point but really don't want to hear from send me email... Tsk, tsk ;)