Moving adverts beamed onto platform walls on London Underground

I was on the way to work this morning at Bank station and on the wall opposite the platform was a moving advert. Initially I thought it was a screen embedded into the wall. On closer inspection I realised it was being projected from across the platform. It stopped being displayed when my tube arrived. A bit of digging turned up this from CBS. No doubt in the future it will be able to display downloaded content perhaps live, although my understanding is that there are some infrastructure issues to be resolved before this can be possible. Wireless isn't available on the Underground for one, and I don't see Transport for London allowing a third party to utilise whatever infrastructure they already have in place to achieve this.

[update] I found a video on YouTube... 

links: digg this    del.icio.us    technorati    reddit