I've been surprised by the success of this 7 min animation on Dewey codes, from the Finnish libraries (kirjastokaista.fi): https://www.youtube.com/watch?v=tF342znnAsM
It's been on the front page of YouTube in Finland for several days now, even as top 1 trending video. It reached 200k views and counting.
As far as I know, no "serious" video on Wikipedia or other Wikimedia projects has reached such a virality. (Although I see a Stephen Colbert and an alltime10s video with 1M views each.) Maybe we can learn something from it?
The video is part of a series by this Tuomas Toivainen: http://www.kirjastokaista.fi/kallen-ja-keijon-kirjastoluokat-animaatiot/ https://fi.wikipedia.org/wiki/Tuomas_Toivainen
Federico