Initial entries were generated from information in the LUG list and CLUE, using positions from the Getty Thesaurus.
Currently, the LUG entry form does not fetch Web pages and parse geo tags. It does, however, use the same elements, and is expected to be updated to monitor Web pages on a regular basis.
You can download the data file used to create this map. There is a little script which will create an xearth marker file from this; see the xearth manpage for details. xearth can put a spinning globe as your root window (X11).