Free iPad app: https://itunes.apple.com/us/app/subtext/id457556753?mt=8&ign-mpt=uo%3D4&uo=4&at=10l6SU
Edmodo app: http://www.edmodo.com/publisher/subtext
Free Android Phone app: https://play.google.com/store/apps/details?id=com.fusionprojects.edmodo
Free iPad app: http://itunes.apple.com/us/app/edmodo/id378352300?mt=8&uo=4&at=10l6SU
Free iPhone app: http://itunes.apple.com/us/app/edmodo/id378352300?mt=8&uo=4&at=10l6SU
Website: http://www.edmodo.com/
Google Chrome app: https://chrome.google.com/webstore/detail/edmodo/fpcdidgjjebefhmlhjlgnkahlimgaemc
Google Apps for Education app: https://www.google.com/enterprise/marketplace/viewListing?productListingId=14101+14209459616553746611
Website: http://www.wikispaces.com/
Website: https://quizlet.com/
Edmodo app: http://www.edmodo.com/publisher?uid=507204
Free iPhone app: https://itunes.apple.com/us/app/quizlet/id546473125?mt=8&uo=4&at=10l6SU
Google Chrome app: https://chrome.google.com/webstore/detail/quizlet/bgofflgeghkhocbociocnckocbjmomjh
Website: http://www.youtube.com/teachers