Virtual reality: computer-generated worlds almost indistinguishable from the real thing.
Nanotechnology: microscopic robots that could bring about heaven on Earth...or hell.
Genetic engineering: someday we may be able to design humans to live underwater or in badly polluted environments. Should we?
Mars: it's time to go there.
Cyberspace: in the mid '80s Canadian William Gibson wrote Neuromancer, set in a gritty near-future where people battled for power inside the world's interlinked computer systems. Several similarly themed novels and short stories appeared around the same time, and the new sub-genre was labelled "cyberpunk" by SF critics. The term and the concepts it implies have now moved into the mainstream.

• Discovery of Martian moons Phobos & Deimos - Jonathan Swift (early 18th century)
  
• Voice recognition for authoring - IsaacAsimov's Second Foundation
  
• Scanner and OpticalCharacterRecognition - RobertHeinlein's TheMoonIsaHarshMistress
  
• Viagra(tm) - PhilDick, Galactic Pot-Healer (1969), chp. 14. He called it "Hardovax". {D.E.C. fan, eh?}
  
• Prisoners used as an organ bank - LarryNiven, "The Jigsaw Man" (196?). In 2006 China was accused of this [www.guardian.co.uk...].
  

Hugo Gernsback was the modern world's first futurist, one who not only speculated about the future, but also worked to make it happen and guide others to it.

He regularly enjoyed dinner at New York's Delmonico's, as did Nicola Tesla,

By this time, Gernsback had become well-acquainted with a number of the world's leading scientists, mainly by correspondence. His position as publisher of Modern Electrics and Electrical Experimenter helped gain the attention of such scientists as Guglielmo Marconi, Robert Goddard, Nicloa Tesla, Reginald Fessenden, and even Thomas Edison. He knew Edison through other connections, as well shall see. A persistent story maintains that Gernsback once went to see Edison in his New Jersey laboratory and nearly wore out the elderly inventor with his intensity. The story has it that Edison was overwhelmed by the sheer volume of ideas Gernsback handed out during the five-hour visit.

He also predicted, more than once, that the first manned Lunar landing would take place between 1970 and 1975.

What he found is a fascinating tale of parallel invention that, in some ways, rivals the simultaneous inventions of calculus in the 17th century by two different mathematicians. The parallel inventions of the transistor in 1948 by Bell Labs’ scientists in the U.S. and Westinghouse Labs’ scientists in the U.K. is a more recent example.