Just a quick FYI, if you are having sync problems using Mozilla Weave with Firefox 3.5 (the little spinner keeps on going forever and the activity log has something like "(NS_ERROR_FAILURE) [IWeaveCrypto.unwrapSymmetricKey]" in it), check out the latest release (at this point 0.5pre1) over at https://people.mozilla.com/~cbeard/weave/dist/latest-weave.xpi , it seems to solve the problem nicely.