
I noticed http://www.tvmaze.com/threads/65/shows-filter-show... got locked, but I had some more ideas :)
With this filter, you add motivation to give ratings. But how to make it easier for people to know what shows they have rated or not?
To make rating easier, you could initiate "popup" - like messages inline at the top of the page after a person has watched an episode of a show they have yet to rate. Something like; "Hello dear Turbopipp, we noticed you just watched a show you have yet to give a rating to. Please give it a rating from 1-10 if you have time. Click HERE if you would like to avoid messages like this in the future."
Also, a list of "not rated shows" would be of great help to get people to rate shows.