This is fascinating. The question that immediately springs to my mind is this: can I look at the crappy failed projects of today, pinpoint the missing technology, and send a note to myself in the future to re-attempt building it when that technology exists? If so, I'd be competitive with the iPad, iPhone, etc.
Yes, you can do that, sending notes into the future is trivial.
Of course, you have to get the timing just right, which is the real trick. Being early, as they say, is virtually the same thing as being wrong.
Also, you have to hope the patent situation is improved prior to your product introduction, because it is already neigh impossible to create a new product that isn't unknowingly violating dozens to hundreds of patents, which (given the purpose patents are supposed to serve) is ridiculous.
