Get your bookmarks, history, passwords, cookies in sync here

This is a Firefox extension, developed by Google Labs.

Google Browser Sync unifies your bookmarks, history, saved passwords, and persistent cookies across all the computers where you install it. It also remembers which tabs and windows you had open when you last closed any of your browsers and gives you a chance to reopen them.

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This is something that I've been looking for for years, yet not prepared to pay for the .Mac subscription which is an alternative.