Dabble DB is a web database system to manage, share and explore data and to build web applications

DataPlace hosts housing and demographic data about communities in the USA. The site assembles a variety of data sets from multiple sources, and provides tools and guides to assist in analyzing, interpreting, and applying the data

GeoServer is an Open Source server that connects your information to the Geospatial Web. With GeoServer you can publish and edit data using open standards. Your information is made available in a large variety of formats as maps/images or actual geospatial data. GeoServer's transactional capabilities offer robust support for shared editing. GeoServer's focus is ease of use and support for standards, in order to serve as 'glue' for the geospatial web, connecting from legacy databases to many diverse clients.

MapWindow GIS 4.0 Open Source Software The MapWindow application is a free, extensible, geographic information system (GIS) that can be used in many ways: As an alternative desktop GIS To distribute data to others To develop and distribute custom spatial data analyses MapWinGIS ActiveX Control At the core of the MapWindow application is the MapWinGIS ActiveX control. Using this control, you can program custom mapping functionality directly into your own software.

MapBuilder is a free web 2.0 web service which lets you tag locations on a map and publish it on your own site.

OpenLayers makes it easy to put a dynamic map in any web page. It can display map tiles and markers loaded from any source. MetaCarta developed the initial version of OpenLayers and gave it to the public to further the use of geographic information of all kinds. OpenLayers is completely free, Open Source JavaScript, released under the BSD License. OpenLayers is a pure JavaScript library for displaying map data in most modern web browsers, with no server-side dependencies. OpenLayers implements a (still-developing) JavaScript API for building rich web-based geographic applications, similar to the Google Maps and MSN Virtual Earth APIs, with one important difference -- OpenLayers is Free Software, developed for and by the Open Source software community.

ArcExplorer is a lightweight GIS data viewer written in Java that is used to perform basic GIS functions (e.g., view, navigate, and query). It is a downloadable application that operates in a stand-alone environment and does not need to connect to a server. ArcExplorer is heavily used in the education world and runs on both Windows and Apple Macintosh computers.

MapMachine is a dynamic atlas you can sue to locate places on Earth, search and print historical, weather, and population maps, and more. Mapmachine is hosted by the National Geographic and powered by ESRI.

ArcGIS Explorer (Geobrowser Client of ArcGIS Server ArcGIS) Explorer is a lightweight desktop client for ArcGIS Server. You can use it to connect via the Web to ESRI-hosted servers that offer unlimited access to ArcGIS Online services. You can also use ArcGIS Explorer to combine ArcGIS Online services with your local data (e.g., shapefiles, geodatabases, ArcGIS Server, ArcIMS, KML, JPEG 2000, GeoTIFF, MrSID, IMG) and other Web services. ArcGIS Explorer lets you perform GIS analysis using tasks (e.g., visibility, modeling, and proximity search).