People are using wiki technology in lots of ways to help each other out.
Starting in San Francisco, in early 2007, social workers and lawyers
got together and built a wiki to host homeless resources -- SFHomeless.net lists all the known service providers plus using wiki
categories, including Food, Shelter, Veterans, etc.
In June 2009 Los Angeles followed San
Francisco: LAHomeless.org. 
Last week Wikipedia founder Jimmy Wales helped launch
tampabayhomeless.wikia.com in his hometown. 
Homeless resources wikis are revolutionizing the use
of social services resources, getting the whole community responsible for
content.