Tools & sites specific to economics.
Website: http://research.stlouisfed.org/fred2/
Free iPhone app: https://itunes.apple.com/us/app/econ-ed-mobile/id501425811?mt=8&uo=4&at=10l6SU
Free Android Phone app: https://play.google.com/store/apps/details?id=org.stlouisfed.econedmobile
Free iPad app: https://itunes.apple.com/us/app/the-fed/id460450216?mt=8&uo=4&at=10l6SU
Free iPhone app: https://itunes.apple.com/us/app/imf-elibrary/id463838393?mt=8&uo=4&at=10l6SU
Free iPad app: https://itunes.apple.com/us/app/imf-elibrary/id463838393?mt=8&uo=4&at=10l6SU
Free iPad app: http://itunes.apple.com/us/app/imf-news-and-data-for-the-ipad/id414587764?mt=8&uo=4&at=10l6SU
Website: https://www.edx.org/
Website: http://www.smgww.org/