It has only a slight connection to Firefox, but I did meet people there doing database-ish things with Firefox extensions to provide a whole experience....
Freebase (http://www.freebase.com) is an odd service. It is a wiki-like database. Anybody can go in, look at a table and decide there needs to be another column on it and add a new column. Anyone can put new data in. Anyone can create new "types" (like tables). There are APIs for managing time information and geo information and all that kind of stuff. They have created the concept of a "Base" which sort of combines a social situation with a custom view of data. It allows a better separation between the model and the view.
And how many places can one go to and talk about the re-contextualization of socially-constructed semi-structured database tables into dynamic entities and not have people get glassy-eyed and start looking for open doors or windows to jump out of?