Read at Kevin Kelly's blog:
"The latest possible date a prediction can come true and still remain in the lifetime of the person making it is defined as The Maes-Garreau Point. The period equals to n-1 of the person's life expectancy.
This suggests a law: Maes-Garreau Law: Most favorable predictions about future technology will fall within the Maes-Garreau Point. (...) Because the official “Future” -- that far away utopia -- must reside in the territory of the unimaginable, the official “future” of a society should always be at least one Maes-Garreau Point away. That means the official future should begin after the average lifespan of an individual in that society.
Why do I blog this? referencing material for my book about technological failures/failed prophecies about innovation.