I've just set up my laptop (where I had running only W7) with a dual boot to run Linux Mint 12 as well.
I have a "Data" partition (apart from the required partitions for W7 and Linux) where I store pretty much everything that isn't software installations (music, videos, project files, etc).
I seem to be able to access that NTFS partition totally fine from Mint (like I've always done with W7), which is cool because I can access all that stuff regardless of which OS I'm using.
I would like to know if it's possible (and how) to go one step further and share programs data between the two OS. One example would be my Firefox and Thunderbird data. For example, in Firefox share my bookmarks (and if I could share history, autocomplete and all that stuff, that would be awesome). In thunderbird, be able to share my mail and configuration, seeing the same inbox, folders, message rules, etc... So if I receive/send an email from W7 and later switch to Mint, I can see that email as it had been received/sent from Mint, and vice versa.
Is this even possible? Or am I asking for too much convenience? If it's possible, any clues on how to set it all up?