I think Rosity does the best they can with contests. Take a peek in the chat room sometime when a big contest is running. You'll find people begging strangers for votes. The next day, a picture that looks like it belongs on mommy's refrigerator will be in the #1 slot. And people will be wondering how in heck that happened. So Rosity usually uses a mix of popular voting and judges, which, though not ideal, is probably the best solution.