An interesting announcement from the largest currently running Drupal site. They've done extensive development to make it work with mobile browsers, as well as integration with IM using Jabber.
The main point is that they've found it very easy to develop custom modules to extend functionality, showcasing the fact that Drupal's core is very well written. Read on for a quote and link to the full posting.
The largest current installation of Drupal 4.4.0 in terms of community size has recently been upgraded to V.2.0. The common code for this blogging community powers motime.com and tipic.com (in English) and splinder.it (in Italian). Among them, there are more than 180,000 registered users.
One of the more interesting aspects of the Splinder/Motime project is the way that it takes advantage of a series of stand-alone modules written by Tipic, Inc. which showcase the flexibility of Drupal's module-based architecture.