insert a feature to sort ALL lists by highest percentage of watched.
One idea occurred to me recently. Would it be interesting if you could pull up a list of lists wherein you have the highest percentage of your watched films? Not so much sorting a list that you've pulled up, but of all the lists on the site, you'd just get your own personal most overlapped. That way you would see some lists that you wouldn't ordinarily come across that would, by definition, best reflect your preferences, and the remaining films you haven't yet watched are probably the best ones for you to seek out.