Rechecked this in Raring (13.04).
This is definetely an issue with Ubuntu One and not with Hamster.
Ubuntu One does not detect the changes of the Hamster.db
Synced my hamster.db and created md5sum.
Then added a few activities to the db and checked md5sum again.
Although the file and md5sum changed, it is not synced.
Rechecked this in Raring (13.04).
This is definetely an issue with Ubuntu One and not with Hamster.
Ubuntu One does not detect the changes of the Hamster.db
Synced my hamster.db and created md5sum.
Then added a few activities to the db and checked md5sum again.
Although the file and md5sum changed, it is not synced.