A Geospatial Content Management System (GeoCMS) is a Content Management System where objects (users, images, articles, blogs..) can have a Latitude,Longitude position to be displayed on an online interactive map. In addition the online maps link to informational pages (wiki pages essentially) on the data represented.
A GeoCMS can have a map of registered users allowing to build communities geographically, by looking at users location. The help of wiki for describing geographical layers present a simple way to solve the problem of geographical metadata.
Since the advent of Google Maps and the publication of its API, numerous users have used online maps to illustrate their web pages. Google Maps is in itself not a GeoCMS but is a powerful building block.
Similarly Mapserver is also a powerful building block for creating GeoCMS.
TikiWiki was the fist CMS to become a GeoCMS in early 2003, it is now becoming popular on various other CMS especially since the publication of the Mapserver API in 2002 to many scripting languages: PHP, Python, Perl, Java,...