John Battelle makes a good point about (a) chasing Google and (b) the key to actually getting somewhere in the advertising market. Of course, this could be considered to be exactly the same as saying "it’s all very well coming up with funky new technology, but does it actually solve a real problem?". For various reasons I’m convinced there is still a huge amount of potential for new tech to offer value to the advertising industry. However I suspect it’s all in the hidden layer behind the scenes (back office, basically): the technology we have for delivering adverts right now is so far from being used to its full potential it does seem a little crazy to be trying to build yet more of it.