Another good article seen on programming.reddit.com:
"... open-source tool based at the University of Washington, won first prize in the scientific software division of Les Trophées du Libre, an international competition for free software."
[ I googled for Les Trophées du Libre (site must be in French, by the name) and found this English version of the site as well. ]
"'I think we can be better than the commercial versions,' he said. 'I really want it to be the best mathematical software in the world.'
"Sage research and student support is made possible by grants from the National Science Foundation. The Sage meetings are supported by various mathematical associations. The project has also received several thousand dollars in private donations. "
Free software brings affordability, transparency to mathematics