Mathematician and author Vernor Vinge on the notion of an 'intelligence explosion' in the January 1983 issue of Omni magazine:
We will soon create intelligences greater than our own. When this happens, human history will have reached a kind of singularity, an intellectual transition as impenetrable as the knotted space-time at the center of a black hole, and the world will pass far beyond our understanding. This singularity, I believe, already haunts a number of science-fiction writers. It makes realistic extrapolation to an interstellar future impossible...
Vernor Vinge's essay on the coming technological singularity (1993): The Coming Technological Singularity: How to Survive in the Post-Human Era
Technological Singularity according to Wikipedia
Fascinating (recent) post by science fiction author Charles Stross on why he thinks the singularity isn't going to happen: Three arguments against the singularity