Ths is the most amazing thing I have seen in a long while.
Ostensibly it allows you to follow the path of Bear 71- who at the start of the story is released into the wild having been tagged. However it is much less linear than even the best examples of interactive film.
As well as tracking the bear, you can interact with other users or follow the story of other animals.
It reminds me of the sand-pit video games, Rockstar have become so famous for doing.
Well worth the time.