GTI Guide uses data supplied by the Open Directory Project. The Open Directory Project aims to be the worlds largest human edited directory.

To acheive this aim (unlike other directories & search engines which uses automated indexing robots or small teams of editoral staff) the Open Directory uses 1000's of volunteer editors, each of whom are knowledgeable about a particular category, to organize portions of the web.

The Open Directory provides the opportunity for everyone to contribute. Signing up is easy: choose a topic you know something about and join. Editing categories is a snap. The Open Directory have a comprehensive set of tools for adding, deleting, and updating links in seconds. For just a few minutes of your time you can help make the Web a better place, and be recognized as an expert on your chosen topic.