For email, use IMAP. However, if you are not already using it, chances are you are with an email provider who doesn't offer it. It might be worth setting up an account with a free provider just for the ability to synchronize. I'd suggest GMX (1&1). Gmail is good but with a recent US decision that all email data should be accessible to the US government, I'd be wary of recommending them any longer. If "IMAP" doesn't mean anything to you, have a look at this: http://www.makeuseof.com/tag/pop-vs-imap/ Lightning can also be synchronized between computers by use of a shared calendar. Again, Google Calendar works well. MS Exchange and its calendar can also be used via davmail. but for the same reasons as mentioned above, I'd avoid any further engagement with Google, I'd also back off from Hotmail and Yahoo, all being US-based. I haven't yet tried GMX for calendars. Contacts and address books are yet another issue; you can synchronize a web-hosted address book in Thunderbird. Yet again, Google Contacts is well supported. For most other providers you have to export the address book and import it into Thunderbird. This add-on: https://addons.mozilla.org/en-us/thunderbird/addon/addressbooks-synchronizer/ lets you synchronize multiple Thunderbirds' Address Books via a variety of internet-based resources.