SimilarMinds.com Compatibility Test
Rates friendship and relationship compatibility between two people.
http://similarminds.com/match/

QuirksMode - CSS contents and browser compatibility
Tests of CSS2 selectors, pseudoclasses and declarations, including compatibility information for Explorer, Mozilla, Safari, and Opera.
http://www.quirksmode.org/index.html?/css/contents.html

CompatibleChoice Compatibility Test
Ph.D. developed compatibility test for couples in seven critical areas that predict long term relationship satisfaction.
http://www.compatiblechoice.com

The Unofficial PCTel modem in Linux compatibility Database
List of all types of PCTel winmodems and their compatibility status. Users can submite their modem information in this site.
http://pctelcompdb.sourceforge.net/

Backward Compatibility Viewer
Web page viewer for checking backward compatibility according to HTML version standards or specific features.
http://www.delorie.com/web/wpbcv.html

White-Box Enterprise Linux
RPM based Linux distribution that retains enough compatibility with Red Hat Enterprise Linux (RHEL3) to allow easy upgrades and to retain compatibility with their Errata SRPMS.
http://www.whiteboxlinux.org/

HyperStudio
A multimedia authoring tool by Knowledge Adventure that provides unique features such as accessing data on the Internet, the ability to create and edit QuickTime and AVI movies, built-in image capture with AV Macs or digital cameras, Mac-Windows-Web project compatibility and the widest range of file type compatibility for graphics and sound.
http://www.hyperstudio.com/

Jung Marriage Test
Jung Marriage Test determines partners' compatibility in the relationship and recommends optimal behavior for your particular couple
http://www.humanmetrics.com/infomate/infomatepass.asp

EMC Electromagnetics Consulting: EMC consulting & advice on electromagnetic compatibility
EMC consulting, advice and support on electromagnetic compatibility of equipment and systems. EMC customers are e.g. aerospace and automotive industry, medical equipment industry, telecom industry
http://www.emc-consulting.de/index-engl.htm

Games Compatibility List
RiscPC x86 card games compatibility list.
http://www.interpages.co.uk/acorn/pccard/compat/gamecomp.html