You can refer to the following links to understand more about the eXo Collaboration Reference Guide:

* [GateIn Reference Guide|http://docs.jboss.com/gatein/portal/3.1.0-FINAL/reference-guide/en-US/html/index.html]
* [OpenSocial gadget|http://wiki.opensocial.org/index.php?title=Main_Page]
* [WebService|http://docs.jboss.org/exojcr/1.12.4-GA/developer/en-US/html/part-ws.html]
* [Chatserver|http://www.igniterealtime.org/builds/openfire/docs/latest/documentation/javadoc/index.html]
* [Vcard|http://en.wikipedia.org/wiki/VCard]
* [iCalendar|http://en.wikipedia.org/wiki/ICalendar] and [its Internet standard|http://www.ietf.org/rfc/rfc2445.txt]
