(Not that anyone will sign up, but if you do, it's mostly just personal tool that isn't exactly full-featured. To wit: Don't forget your password.)
It's pure Python built around Django. It's a super thin wrapper over a postgres db. It's honestly little more than a web interface for the database. If anyone wants to make their own, all the code is here:
The del.icio.us API would allow them to grab pretty much all of it anyway. I've already migrated mine out to a couchdb-based clone: http://xlson.com/2011/01/13/out-off-delicious-and-into-your-...
This has the nice benefits of always being local and being impossible to take away from me. :)
(well, I did break my couchdb build with an experimental branch on an experimental OS, but I'll sort that out later)