Mainstream support is the five year period during which Microsoft provides free Updates, Security patches and fixes. After exiting this phase Microsoft provides some years of extended support during which we get Security updates but other updates are often paid. The Mainstream Support for Windows 7, Windows Server 2008 and 2008 R2 and Windows Storage Server 2008 ends on January 13 and extended support for these products end on 14 January, 2020. End of support means there will be absolutely no updates, free or paid, security or non-security.
Support for Share Point 2010 and Office 2010 with Service Pack 1 ends this October 14. Complete end of support for Microsoft Windows Server 2003 is also approaching on July 14, 2015 and Microsoft is trying to convince them to upgrade to Windows Server 2012. Mainstream Support for Windows Phone 7.8 is also ending this September 14.