Andrew Gerrand worked with me on Camlistore too and is one of the Upspin authors.
The main difference I see is that Camlistore can model POSIX filesystems for backup and FUSE, but that's not its preferred view of the world. It is perfectly happy modeling a tweet or a "like" on its own, without any name in the world.
Upspin's data model is very much a traditional filesystem.
Also, upspin cared about the interop between different users from day 1 with keyservers etc, whereas for Camlistore that was not the primary design criteria. (We're only starting to work on that now in Camlistore).
But there is some similarity for sure, and Andrew knows both.
This is pretty much correct. Upspin is way more filesystem-like than Camlistore, but I would emphasize Upspin's single global name space, rather than the filesystem-ness.
I think both Camlistore and Upspin have promising models.
bradfitz has already replied, I just wanted to add what seems to me to be the focus of both projects, because they are different:
Camlistore aims to be your repo of all your stuff that you may want to share with other people at a later time. It wants to be the repository of all your life and everything that happens.
Upspin aims to be a unified protocol for all applications to access (and possibly modify) data, wherever it is: maybe it is your website on your server, maybe it's a NASA dataset on some S3 tenant, maybe it's an imgur gallery, maybe it's an OpenStreetMap dump of their DB; the goal AFAICS is to give any application access to data regardless of where and how it is stored, so that applications can do what they're best at.
