The online service formerly known as FolderShare has been reborn, with a few enhancements, as Windows Live Sync. I used it briefly during its beta period in the last few months and it seemed fast and reliable.
You can get more details from this introductory blog post by the Live Sync team. A new discussion group is also available for support.
If you have any experiences to share, please leave them in the comments.
Ed Bott 
I’m a long-time user of Foldershare on both PCs and Macs. It’s become an indispensable part of my business workflow, which for a free product, is a little risky…
Unfortunately this upgrade is currently in the ‘disaster’ realm, with the Live Sync team forced to completely disable the Mac client due to what sounds like a pretty massive infrastructure bug. For such a showstopper, I can’t understand how it got through the beta testing.
It is hard to complain though, because it is a free product. It’s time like this where I almost wish I was paying for the service, because then I could feel like I could really get angry about them taking away a mission-critical aspect of my business workflow.
But it’s free, so I’ll give them a chance to fix it. No doubt the team is pretty stressed out at the moment! So much for a big successful launch with lots of kudos – instead they’re going to be subject to the typical ‘bloody Microsoft’ response.
Upgraded four machines, all Vista. Takes between 1-4 logins to succeed. Other than that, no problems.
According to the Microsoft employees posting on the newsgroups, there is a problem with the authentication portion of the Mac client, which is hammering the authentication servers. This overload is what’s causing login problems for the Windows client as well.
Does Windows Live Sync use the same technology as MS Groove?
Betsy, no, Live Sync (nee FolderShare) and Groove use completely different technologies.