http://advogato.org/article/994.html
Peer-to-peer git repositories. Imagine a MediaWiki with the data stored in git, and updates distributed peer-to-peer.
"Imagine if Wikipedia could be mirrored locally, run on a local mirror, where content was pushed and pulled, GPG-Digitally-signed; content shared via peer-to-peer instead of overloading the Wikipedia servers."
This would certainly go some way to solving the "a good dump is all but impossible" problem ...
(so, anyone hacked up a git backend for MediaWiki revisions rather than MySQL? :-) )
- d.