Use SyncKolab to synchronize your Thunderbird Data
If you happen to use an e-mail provider that's offering an IMAP-server (or you are boosting your own (mail-)server), this might be for you, because chances are if you are using IMAP, you're the "portable" type of user.
As some of the more regular readers may know, I'm all into the whole 'portable' thing, and am constantly looking for ways to use stealthy software, sync my data or access it wherever I go. So it's not surprising I stumbled across the SyncKolab Thunderbird extension some time ago looking for a possibility to sync my contacts across different computers as easy as my bookmarks using Foxmarks. Didn't turn out that time, I just couldn't get it to work.
But now, you may have guessed it already where this is heading, version 1.0 is out and, what can I say, it works like a charm, and not only for my contacts, but for my lightning-powered to-do's and calendar items as well!
The whole thing uses the Kolab 'protocol' (in lack for a better word), which uses iCals and E-Mails containing xml-files to, among other things, store the items in your IMAP-Folder.
There's a pretty good tutorial how to set it up as well, but it's principle is rather simple. Choose an IMAP-Account, the items you want to have synced (contacts, calendar and to-do; the latter two require lightning to be installed) and where to store the data in the IMAP folder structure. I used a new folder named Synckolab containing subfolders for each of the groups, though I don't know if it's necessary to split them up.
Conflicts are resolved by using a pre-defined setting (always use server-side or client-side), or by asking the user, which is always my personal weapon of choice.