Google"s latest FireFox extension, Google Browser Sync, "continuously synchronizes your browser settings." Browser Sync keeps all your bookmarks, history, persistent cookies, saved passwords across multiple computers. It also saves any tabs and windows you had open during your previous session and prompts if you would like them reopened.
Users can choose which items to keep syncronized and which items should be encrypted. Each time FireFox is started the extension updates all of your selected items. This leads to an increase in startup time but Google states they are trying to decrease the delay.