No text. Really.

Fun :)

And shared experience, so someone else will have a little less tinkering to do when they look at this and go "Hey, I wonder if I could..."

For anyone who doesn't feel like clicking through the slow copy-and-paste blog to get to the actual NewScientist article:

http://www.newscientist.com/article/mg20827875.800-worlds-first-ice-touchscreen-virtually-burns.html

Blame the idiotic coverage rather than the folks building the wall. They're well aware it was just a cool (sorry) art piece. And shared their experiences for anyone who wants to build or build on the design.

That work was just published at the ACM Interactive Tabletops and Surfaces conference, so there is a rather more coherent explanation (and another video) at:
http://www.dfki.de/its2010/papers/sp199.html

(Not affiliated with either group, but ITS was a lot of fun)

Google must have "forced" Apple to drop Skyhook as well. Or maybe there were reasons to develop a competitor, rather than continue to deal with Skyhook. Like Apple did.

Seriously, when did "Oh no, we're being forced to compete! Let's sue everyone!" become an acceptable business plan?

Digital information is *very* easy to authenticate and *very* hard to forge -- think SSL -- in comparison something like physical bills.

Digital information being easy to copy means that you *detect* the copy, rather than trying to *prevent* it. DRM tries to prevent the copy. All Bitcoin determines is whether you got the oldest copy (and the how is in their tech report).

Approaches vary but that is far from an obscure threat. Some, like I believe Bitcoin does, do a global check of the current owner of the coin (and yes, handle the obvious race conditions). Others make it relatively expensive to establish a new identity, provide probabilistic discovery of double spending...

Well, close. Money needs to be hard to replicate _without getting caught_.

Part of the design of digital currencies is making it so that double-spending is likely to be detectable. Bitcoin seems to broadcast all transactions to the network, but I admit I just glanced at their technical paper.