I am willing to implement website where will be top 10 best members' pictures or something like that. Before voting for pictures or uploading pictures people will have to register first. But how could I protect my website from multiple accounts? Store IPs to database? But will it help me while there thousands proxies out there? What should I do? Thank you.
edit: maybe I could make accounts paid, for examples 0.99$ for month via paypal and somehow do no let people register twice with the same paypal and IP? Is it possible?
Use a confirmation code that is sent to mobile no upon registration. and confirm it. like google.