"OpenLayers has been getting some high-profile usage lately,
including on EveryBlock, the geographic news site run by Django
creator Adrian Holovaty and others, and also as part of the mapping
stack Barack Obama's campaign used to help support his successful
US presidential bid.
"Geographic intelligence company MetaCarta originally developed
the library, but eventually released it to the public under a
BSD-style license. OpenLayers implements the Open Geospatial
Consortium's Web Map Service (WMS) and Web Feature Service
protocols. The library is in active development, and version 2.7
was released in September. To use OpenLayers, you can either link
to it, or download it from the OpenLayers Web site.
"OpenLayers works either with data you're serving yourself,
using a package such as GeoServer or MapServer, or with data others
are publishing via WMS. There is no easy way to search for WMS
servers with data to display, although ExploreOurPla.net does offer
a searchable index it claims includes more than 30,000 publicly
accessible layers on more than 200 servers."
