The Africa Map project, currently in beta, is an online map and data viewer created by Harvard University. The map combines data sets of numerous categories from a wide variety of sources, allowing thematic maps to be viewed and explored. The purposes of the project, according to the project web site:
Interact with the best available public data for Africa
See the whole of Africa yet also zoom in to particular places
Accumulate both contemporary and historical data supplied by researchers and make it permanently accessible online
Work collaboratively across disciplines and organizations with spatial information about Africa in an online environment
"Envisioning Development: What is Affordable Housing?" is an interactive Flash-based map of housing and income statistics on a neighborhood-by-neighborhood basis throughout the New York City area. Although I've seen similar statistical/analytical interactive maps with similar data plenty of times, the aesthetic design and information visualization "impact" of this map is almost breathtaking. This map is part of an online resource toolkit for urban planning and land use education based around NYC, offered by the Center for Urban Pedagogy.
MoveSmart.org recently launched their Neighborhood Finder, an online web application for people seeking to move to a new neighborhood in Chicago - and coming soon, other cities around the US!
The Library of the University of Arkansas has a very impressive collection of international and US geodata repository links - mostly geospatial data and attributes. I'll be poking around in here for hours, I think! A wide variety of topics and well-organized to boot.
Movesmart.org is a new website and nonprofit organization dedicated to helping housing seekers find neighborhoods that meet their needs while at the same time promoting diverse, healthy, and vibrant communities. The organization's core offering is an interactive mapping application called Neighborhood Finder (launching late summer 2009), which provides a geographic interface to many different types of data about neighborhoods. Other resources include a series of informative guides about relevant housing and neighborhood topics and a blog about fair housing and other similar issues.
You can learn more about Movesmart.org, as well as watch a short video about the organization and the website, by visiting http://movesmart.org/about (new window).
The California Inclusionary Housing Policy Database provides a geographic search capability for users seeking information about policies in specific regions or municipalities in California. The database, possibly the first of its kind in the US, is managed by the California Coalition for Rural Housing, and was developed by MT development partner CTC in 2008-09 thanks to funding from the S. H. Cowell Foundation. The database and associated website are built on the Drupal content management system, using GIS functionality supplied by Google and CTC's mapping software.