The idea of technological singularity is roughly a state in the future when machines are smarter than humans, which in turn sets the stage for them to make even smarter machines etc. I understand that there are a bunch of people who think Singularity is exceedingly near with Ray Kurzweil’s The Singularity Is Near arguing that it is likely to be attained by 2045!!! Elizer Yudowsky's posts on http://www.overcomingbias.com/ have a similar theme too!
Most of their arguments for the singularity being near have to do with the highly super-linear impact of a lot of technology which tend to build on one another etc. I would like to add a new argument borrowed from the movie, idiocracy!
Idiocracy makes that point that the last 50-100 years have been a turning point in the history of human evolution. While higher intelligence caused better survival and reproductive success for several million years, in the last few decades number of surviving offspring is undoubtedly negatively correlated with intelligence in most societies. The movie is a hilarious take on a society 500 years hence wherein society has undergone a heavy dumbing down both for the aforesaid genetic reasons, and also since popular culture heavily discourages activities that involve usage of intelligence.
So here is my two cents from a discussion with Jonathan. One more reason to believe that the singularity is near is that humans are getting dumber and consequently the machines could cross human intelligence (aka. Turing's test), simply as a result of humans getting dumber. :P