To get an idea of it I recommend to watch this lightning talk Marc-Andre Lemburg gave at the EuroPython 2009.
African press is speaking about the start of the pilot phase:
Twittori.com is our current project that adds geo tagging to Twitter messages. It is very easy to use and intends to bring a more useable geo dimension into the Twitter World.
Unlike other services this is done by a tiny URL that itself contains all geo location informations e.g. http://GE0.at/0MbEX8 which locates the Eiffel Tower in Paris. This is achieved by a modified ‘geohash’ algorithm (more on that at Wikipedia).
The second unique feature is that users can follow places in a similar way than they are used to follow users on Twitter. Therefore the earth is divided in discrete squares of about 0.25 square kilometers. You can keep updated by subscribing to a RSS Feed or visiting the web site. Continue reading