Description:First commercial microkernel OS
Inventor:Dan Dodge and Gordon Bell
Impact on civilization: Showed it was possible to have a multi-user, multi-tasking, multiprocessor OS with real-time performance running on a PC with only 64K of RAM. It and its successors (QNX2, QNX4, QNX Neutrino RTOS) spawned many uses in reliability-critical industries.
Visicalc introduced on PC in 1981
Description: First commercial spreadsheet
Inventor: Dan Bricklin and Bob Frankston
Impact on civilization: Made personal computers a serious business tool instead of a hobbyist orgame machine. Visicalc was first created in 1979, but it effectively launched the Personal Computing industry, by bringing IBM to the party in 1981.
I remember this pretty distinctly--my Dad bought Visicalc for the Atari 800. It made heavy use of the slash key for doing almost anything. It was pretty limited compared to Excel. At the time, it was amazing to see numbers magically recalculated all over the page when you changed one little thing. All done in 48K. If you're feeling nostalgic, you can run a real version of this on your Windows PC for old-tymers found on Dan Bricklin's website.
Description:Common PC OS
Promoter/Inventor:Bill Gates / Tim Paterson
Impact on civilization: Created a common architecture for software development, spawning an industry. And created the world’s wealthiest person. (As of Mar 10, 2010 due to Mr. Gates' generous philanthropy and the depressed state of the stock market he was bumped down to the second wealthiest.)