LiveRail is a video advertising network that eschews the usual pre-roll and post-roll model to put the user in control, ad boxes are shown next to the video so the viewer can choose to click on the boxes to play the ad, see the example below.
I think this is a very good value proposition for advertisers as they only pay when there ad rolls. Personally i’m a huge fan of opt in advertising, I experience this when I’m fast forwarding on my tivo and sometimes back up to watch an ad i like. Geico cavemen anybody “it’s mother, i’ll put her on speaker”.
Currently it’s in an invite only beta, you can read a much more in depth analysis from Read/Write Web here.