Update Sept. 9, 2010: The Weave extension mentioned in the post below has been renamed Firefox Sync (Mozilla Firefox 3.6.x series) and is included with the Mozilla Firefox 4.x Beta releases.
Several months ago I chanced across the Firefox Weave extension that lets you synchronize your bookmarks (aka Favorites), passwords, (browser) preferences, (browsing) History and even open tabs across multiple Firefox setups. The extension works with both installed and Portable Firefox version 3.5 or later (including 3.7 with Nightly Tester Tools installed) . As well as the mobile Fennec browser!
The initial Weave release was limited to bookmarks and passwords. So after playing around (er, testing) I stopped as I didn’t really find much use for the plug-in. Plus (this is important) I forgot the ID I’d registered with and the passphrase. So there’s probably a copy of my data somewhere on Mozilla’s servers that I (and everyone else) is locked out of!
By default your data is stored on Mozilla’s Weave server. If you are wonderfully paranoid about ‘Big Brother’ and have the technical skills you can roll your own Weave server on LAMP.
Weave has improved a lot since those early days. And in Dec 2009, it has gone from Beta to RC. But some things haven’t changed. Like the authentication interface. If you forget the email account you used to sign up (not a problem with most people but it is for me :). Or worse (everyone) forget your pass phrase. You are permanently locked out of your account!
Firefox setup is easy. Firefox users can click this link. Just visit Mozilla Labs. Then restart Firefox (which can be bore even though it takes a few seconds). You’ll notice a new status bar icon to the extreme right. That you right click to setup your account. Or if you already have an account to sign in.
New users need to provide an email ID. Then authenticate that it exists. You have to provide a sign-in name and a password. And the first time you sync data a pass phrase as well. The more secure this phrase. The more secure your data.
Once you set your pass phrase you can’t change it later without first deleting all your data. So when registering I highly recommend using a highly secure 16+ character mixed content (i.e. lower & uppercase alphabets, numbers & special characters) phrase. Make sure write it down because if you every forget you won’t be able to synchronize your data.