CartoDB makes data-driven map visualisation tool. It's very easy to upload a couple of spreadsheets of data, with latitudes and longitudes or addresses, and turn them into clickable markers on maps. There are several types of pre-canned visualisation, such as categories, choropleths or even animated "torque" maps. It's also a sophisticated platform allowing complex visualisations to be built up using Javascript and the CartoDB API.

Open source map design studio for creating and styling web tile maps, based on either provided free MapBox Geodata, or data imported as a variety of file formats. It uses the CartoCSS styling language to customize interactive visualizations, with powerful control of symbols, zoom levels, labels, and other cartographic details. The finished maps can be exported either as images or tiled web maps. Though the TileMill software is free, there may be a fee to host the created tiles on MapBox or elsewhere.

A global geographical database that may be used to identify and tag all references to location. The database contains over 8 million entries, each of which possesses a geographic name (in various languages), latitude, longitude, elevation, population, administrative subdivision and postal codes and information on unique features.

Features:

Built upon web service, enabling transparent look-up and use of content through third-party tools and sites

Browse by geographic location, country name, size of geographic region and other categories.

Full text search support

Extensible, enabling users to expand existing information or contribute new content

Support for the World Geodetic System 1984 (WGS84) co-ordinate system