Arcade Fire's new music video for Sprawl II (Mountains Beyond Mountains) comes in two versions - one of which allows viewers to "direct" the content: By clicking the mouse or moving in front of the camera built into their computer or phone, users can change the action in the video. I've tried it - but it's still not clear to me how the motion in front of my webcam causes the dancers onscreen to respond (if it does at all?) - I'm curious what other users think...
Arcade Fire's last big experiment with interactive online video was a piece (incorporating images from each user's hometown) created by writer/director Chris Milk - The Wilderness Downtown - set to We Used to Wait. That Wilderness Downtown experience wasn't totally satisfying for me either (i.e., the windows with images from my hometown opened and closed in ways that were perplexing and kinda ugly).
Nevertheless, I really appreciate what Arcade Fire is attempting - using their musical fame to pioneer a new terrain of visual interactivity.
If you are interested in the Arcade Fire interactive experiments, I highly recommend the short film (below) about the band's collaboration with Chris Milk to release cascades of beachballs during their last song, “Wake Up,” at Coachella 2011. Notice that Chris Milk talks about creating "emotional stories..."