As of Sunday the 17th of August, Mozilla Weave seems to be back up and working. I haven’t been able to use the service for at least 2 weeks, but I can confirm that I can login, and sync all my Firefox 3 settings.
The sync process is still slightly slow, but it is working again. I use no fewer than 4 computers on a daily basis, and I have found it is hard to function properly without such a browser sync feature at this point.
This is something that Microsoft really should think about integrating into Internet Explorer 8. We could set this up to use our hotmail/live/msn email logins as the sync username. I can see the process being really smooth. I can’t guarantee that I would use IE again, but this might get me at least slightly intereseted.