Yahoo! Updates, the company's answer to Facebook Connect, became available on more than 600,000 websites today with the launch of a new partnership with commenting infrastructure company JS-Kit. Whereas Facebook's technology for tying profiles and activity updates between sites around the web has raised concerns about proprietary control over data, Yahoo! has implemented the open standard OAuth in its system.

By partnering with JS-Kit, a service that powers comments and ratings on sites big (like AOL and Sun Microsystems) and small (JS-Kit bought up old school market leader Haloscan in July), Yahoo! Updates is coming out of the gate in a big way. How does its technology compare to Facebook Connect?

The vision for all these kinds of systems is that allowing readers to authenticate themselves with a trusted 3rd party makes them more likely to post comments, offers exposure to site owners when comments are syndicated into activity streams on bigger sites and should allow site owners to access verified information about their readers' profiles and interests. That last part is still something we're waiting for, but that should be part of the value proposition to site owners.

Facebook Connect has been lauded for its usability; so much so that advocates of OpenID felt deeply threatened until Facebook teamed up to work with them on the OpenID user experience. In contrast, the Yahoo/JS-Kit user experience is immediately quite usable and full-featured. The same type of pop-up window asks users to grant permission to JS-Kit (or any other site using Yahoo! Updates) to access their Yahoo! profile information. There are a few extra boxes users have to click in order to grant that permission, but that's the extent of the complications. You can test the implementation on this page.

We're quite impressed with the technology and we're always appreciative of the way that Yahoo! supports open standards. It's not as if the company is accepting 3rd party OpenID login on Yahoo! sites yet, but all these other little steps are quite significant.

One thing that Yahoo! doesn't currently offer is syndication of off-site activities into Yahoo! properties. The company says that's coming soon.

In the coming months, as Updates are implemented across Yahoo!, publishers will enjoy referral traffic back to their sites from across the Yahoo! Network (more than 500M+ monthly unique visitors)...Yahoo! Messenger, Yahoo! Mail, Yahoo! Toolbar, Profiles, etc.

If you thought Facebook represented the mainstream face of newsfeeds, 3rd party identity authentication, etc. just imagine what Yahoo! could do. The only question is whether the giant company will move fast enough - Facebook is very close to having stolen its thunder already. Yahoo! has been talking about "opening up" and integrating social data across its sites for months, Facebook tends to be much, much faster at taking action and innovating.

Facebook Connect is also available on JS-Kit supported pages, so it's not as if Yahoo! has surpassed Connect. We've asked Facebook for a precise number of pages that Connect is available on and are awaiting a reply. We do know that the company says that 6,000 developers have implemented Connect, but for all we know that number includes JS-Kit with its 600,000 sites as just one developer.

What do you think of the new JS-Kit/Yahoo! tie-in? Would you use it on sites where both it and Facebook Connect are an option? You can test Facebook Connect here on our site or both Connect and the new Yahoo! Updates commenting over on Guy Kawasaki's blog.