It is the result of a 2007 energy conservation measure passed by Congress that set standards essentially banning ordinary incandescent bulbs beginning in 2012. Other countries are doing the same. Some stores have announced phasing out incandescents as early as the end of 2010.
Much controversy remains as to whether the high cost of replacement bulbs is really offset by the savings in electricity. Of course, the US does not produce the replacement bulbs, they all come from overseas, so US jobs are leaving with the bulbs. My bet is that LEDs will emerge as the winner over all the others. If you love your ordinary bulbs, stock up, because they will cost more as they become less available.