Dates for inventions are often controversial. Inventions are often invented by several inventors around the same time, or may be invented in an impractical form many years before another inventor improves the invention into a practical form. Where there is ambiguity, the date of the first working version of the invention is used here.
1990: World Wide Web: Tim Berners-Lee
1993: Global Positioning System: United States Department of Defense
1993: Blue LED: Shuji Nakamura
1994: Wiki: Ward Cunningham
1997: Non-mechanical Digital Audio Player: SaeHan Information Systems
1997: Wi-Fi: Alex Hills
1998: Viagra: Nicholas Terret, Peter Dunn (scientist) and Albert Wood