The first is what I call the ``Oh Wow'' view of things. You look at the curve and draw the obvious conclusion--it's going to go on climbing to the sky forever.
Now I don't mean to disparage this view; most people err on the side of conservatism--they don't realise just how far a trend can go once it's set into motion. But nothing grows forever.
In evaluating any growth trend, whether CPU performance at constant price, world population, or Marin County real estate prices, you have to ask, ``what are the fundamental limits to this growth.''