the transcript of vernor vinge's SALT lecture on feb 15 goes into great detail, but here's a quick recapitulation of as much of what was said as i can be bothered to put down:
in summary: technological progress is bootstrapped by prior technological progress -- hence the curve of development captured in moore's law. we stand on the shoulders of giants to create the next generation of giants. the contention is that we now approach a state where the combined processing power of the hardward and software we create is reaching human capacity. at this point, we will be able to use these human-level tools to create machine intelligence that exceeds that of humanity. literally, superhuman intelligence. at this point, all bets are off. we cannot imagine, as humans, what a world with superhumans will be like. this is the singularity.

vinge and others who believe in different flavours of singularity (teilhard de chardin's omega point, various ideas of the human attainment of godhead, etc) think that it is fast approaching and inevitable. vinge's SALT lecture considered alternative situations in which the singularity does not take place. he gives several pathways by which this could happen. the most compelling was the one governed by incentives. the exponential growth of processing power that moore's law describes is generally driven by economic and strategic incentives and limited by physical constraints. if the economic or strategic drivers were countered by sufficiently large disincentives, growth in processing power would taper off. one example of how this might happen: in the first implementations of truly large scale automation, a major bug causes an enormous catastrophe (an n-way collision due to a bug in an air traffic control system).

several key thoughts emerging from this: the idea of long-term thinking also brings up a number of questions and thoughts:
my favourite quote from the night, and one which theme i've explored before,
you don't understand the destructive impulse of people who like to break things which are beautiful.