|"Tatort+: The Forest Stands Dark and Silent", SWR/ARD|
"Tatort+: The Forest Stands Dark and Silent" ("Tatort+: Der Wald steht schwarz und schweiget", SWR/ARD, archived version) extended the story beyond the TV screen and turned the audience into investigators. The extensive (now offline) point-and-click adventure game was massively spread on Facebook and Twitter and proved to be greatly successful. 110.000 users registered, more than 20.000 of them solved the case, in just one week.
(Which by the way was too much. The servers kept going down.)