**On March 31, 2011, Windows Live Sync will stop working! **

After March 31, this program will no longer sync your files between your computers and you won't be able to access your files remotely from sync.live.com.
To deliver a better product for all customers, several services will be combined into a new product called Windows Live Mesh (1).
Windows Live Mesh offers similar features to Windows Live Sync, but with several performance and reliability improvements.

With Windows Live Mesh, you can:

• Sync folders between computers (PC or Mac).
• Sync folders to a new online storage space.
• Sync your program settings for Internet Explorer and Microsoft Office.
• Connect to your PCs remotely to access their files and run programs on them.

Note: Windows Live Mesh is available only for Windows 7, Windows Vista, Windows Server 2008, and Mac OS X version 10.5 or later, NOT AVAILABLE for Windows XP

Windows Live Sync will continue to run until March 31, 2011. However, it is no longer accepting new customers.
On March 31, 2011, you will no longer be able to sign in to Windows Live Sync on your PC, Mac, or on the web.

(1) Windows Live Mesh

(2) http://explore.live.com/windows-live-mesh?os=winxp

If you like this software, try Windows Live Mesh.. essentially the same thing, but I think it runs smoother and has more options...I really like the Live Desktop with windows live mesh as well.. you can browse your files online in a nice interface!

Allows you to choose folders you wish to sync across systems. By and large, it works very well and I have come to depend on it but several features are holding it back from being the best one out there.

Features it needs

• Ability to synchronize without a user being logged on. Specifically, it does not install as a service.
• Ability to filter specific files or file types in a directory from being synched.
• Ability when setting up directories to be synched to better compare if files are actually the same or not.
• Option to purchase online storage to sync to (similar to a Dropbox or SugarSync)

It's just to bad that it seems Microsoft has abandoned this great piece of software.

I like Live Sync for synchronizing remote directories, freely selectable, without a web proxy.
But the proxy setting mask http://screencast.com/t/YjZiMzBmYTUt for Live Sync is missing an entry for username and password as has DropBox or SugarSync. Therefore, Live Sync does not work in a corporate network with a HTTP proxy with password protection, where DropBox and SugarSync, however, work very well: ScreenShot of DropBox proxy input: http://alternativeto.net/desktop/dropbox/ (2. ScreenShot from left). In addition, SugarSync provides even a domain input as a complement: http://screencast.com/t/MzgwYzc0OWIt .
My suggestion: establish the proxy server input for live sync, as with DropBox with a username and password input for HTTP and Socks proxy or with additional domain entry like SugarSync.
(Interestingly Evernote works in a corporate network which is proxy and password protected, although in Evernote you must not specify a proxy).

DropBox: only one folder with subfolders as a complete package with the same synchronizing partners for the package.
Live Sync: up to 20 folders on different locations can be freely selected: very flexible.
Each folder can have different synchronizing partners.

Synchronizing of folders of more then 2 computers not with SugarSync for free
I wanted to sync a folder on my computer with a synchronous copy of this folder on the computer of a aunt, 200 km away from me for purposes of remote software installation.

First I wanted to do this with sugarsync, where I already have 2 computers synchronized (free up to 2GB) : my private and my office computer.
But SugarSync does not allow to synchronize a 3rd computer for free.
So this is only possible with Windows Live Sync.

Following the information of http://en.wikipedia.org/wiki/Windows_Live_Sync :

A maximum of 20 folders (or "libraries") may by synced, including libraries shared over the internet. Each library can contain a maximum of 20,000 files and each file cannot exceed 4GB.

I would bei interested about a link to a confirmation of this Wikipedia information from Microsoft itself.

After setting up the synchronisation for one folder between my PC and my aunt's PC with Windows Live Sync , this works very well to our fullest satisfaction.

This is the closest comparable tool to DropBox that I've seen and liked. I actually use both for different purposes. I run Sync on my wife's laptop to automatically back up her My Documents to our desktop computer. But I used DropBox to share files to work, primarily because I can also run it on my iPod Touch.

Sync is pretty stable/reliable, free, and very flexible. I really like that you don't need to put the files you want to sync into a separate folder, as per Dropbox.