NEW YORK ( TheStreet) -- For Facebook, which will carry a ticker symbol of FB, to receive a $100 billion valuation when it makes its IPO debut, investors will have to make a lot of assumptions about their future growth. Do you remember when we were going to run out of oil in 1980? Or what about solar energy and wind power? Remember when that was going to be the wave of the future? How about when every TV spot had "AOL Keyword:...." in it? Or when Rupert Murdoch was so smart for buying MySpace for "only" $550 million? Or how about when all the U.S. banks had to be nationalized back in 2009 and the world was going to end? And then Ben Bernanke was debasing the U.S. dollar by running the printing presses and gold was going to go to $10,000 an ounce?