Rated 3 out of 5 stars

SafeCache 1.0 in:
http://crypto.stanford.edu/SafeCache/stanford-safecache-1.0.xpi
You can download it with Clipboard-save-as https://addons.mozilla.org/en-US/firefox/addon/clipboard-save-as/

It seems to work on FF 6.0a1 (nightly at this moment) after tweaking maxversion into install.rdf file to allow install. But also I found a strange behavior in the tests
http://crypto.stanford.edu/sameorigin/safecachetest.html
Doing refresh using cache (F5), if all cookies are allowed with SafeCache 0.9 or 1.0 on, there's some times radom id with same site cache cookies, is equal to radom id with different referrer cache cookie. Also, if third party cookies are blocked, this problem is almost constant each time I refresh; and also, random id with third party cookie don't get renewed in each refreshing, as the test designer asserts.
But I still don't know if the problem is in the extension or in the web test. If you know other site to do the same tests, please post it.

Besides it would need an update to allow install on new FF versions.
And there's also a flaw in the options box / privacy tab, where the SafeCache setting is, SafeCache assumes there's a cookie subsection like there was in FF 2, but it is not for versions beyond FF 2 , so after installing you'll find an new empty section like this http://img291.imageshack.us/i/safecacheoldcookiessect.png To fix this, you have to:
- Uncompress the extension (or the easy way, open it with 7-zip file manager).
- Uncompress ..\chrome\stanford-safecache.jar (or open it nested with 7-zip file manager).
- Edit file ..\content\pref-privacy.xul (F4 in 7-zip file manager) and remove the following line:

<groupbox id="cookiesGroup">;

- Zip compress again stanford-safecache.jar and substitute the original (apply changes to file in 7-zip file manager).
- Zip compress the new .xpi file (apply changes to file in 7-zip file manager).

Rated 3 out of 5 stars

With FF 3.6 (after making maxversion trick in install.rdf to allow install) I've observed mixed behavior in the tests http://crypto.stanford.edu/sameorigin/safecachetest.html Doing refresh using cache (F5), if all cookies are allowed with SafeCache 0.9 or 1.0 on, there's some times radom id with same site cache cookies is equal to radom id with different referrer cache cookie. Also, if third party cookies are blocked, this problem is the constant almost in all refreshing; and also, random id with third party cookie don't get renewed in each refreshing, as the test designer asserts.
Don't know if the problem is the addon or the web test, if you know other site to test the same features, would be of great help if you post it.