When you connect with a website, it can access information you’ve added through Facebook to allow you to interact with your friends in new and interesting ways. The Platform Developer Terms of Service restrict how these sites can access this information, and all sites are contractually obligated to respect the privacy settings you’ve chosen for your account. These are the same terms that developers who have created the applications you use on Facebook must follow.

This means that if you’ve blocked a user on Facebook, that user will not be able to see you on a "connected" site. When other users connect with a website, those users will not be able to see information you’ve added through Facebook that they wouldn’t otherwise be able to see simply by browsing Facebook. You can decide what types of information your friends’ applications can access from the "Applications" section on the Privacy page or opt-out of Facebook Platform entirely.

Facebook has enabled third-party websites to use Facebook’s login and authentication system through a program called Facebook Connect. Facebook Connect allows users to take their Facebook identity, network, and privacy settings with them as they browse and interact with the rest of the Web. Connect-enabled sites often provide an option to log in to Facebook directly from the site itself. When you see this, you should make sure that the login opens in a separate browser pop-up window, and that the Web address (URL) for the pop-up contains the proper "www.facebook.com" domain. If it does, you’ll know that it’s a legitimate Facebook page and not a phishing attempt, and you can log in safely and securely. Note: if you’re logged in to Facebook, the Facebook Connect partner site should only ask you to "authorize" that site.

Just as News Feed has always enabled you to see what your friends are up to on Facebook, now, depending on the privacy settings of everyone involved, people can share many of the actions they take on the rest of the Web as well. People always have the option to refuse a News Feed story from another site. We want to give you the stories we think you’ll find most interesting and relevant; by including the actions you and your friends take both on and off of Facebook, we believe we will make News Feed even better at helping you stay in touch with your friends.

Facebook cannot track your actions on external sites unless you decide to connect your Facebook account to that site and/or explicitly decide to publish a story to your Wall. For example, if you are on Digg, and digg an article, or comment on an article, Facebook will only be notified of the actions for which Digg wants to create a story. Facebook will have no access to other actions you have taken or other information involving your Digg account.

To take advantage of the ability to generate stories from another site, you must "connect" your Facebook account to that site, or otherwise be logged into Facebook while you interact with one of these sites. You will always be notified and given the opportunity to opt out of having any particular story published.

Facebook Connect launched in December 2008 and is currently available on more than 15,000 websites, devices and applications, including CNN, CBS.com, Digg, Yelp, YouTube, Xbox, and Nintendo DSI. If you can’t find Facebook Connect on your favorite sites, contact the website administrators and make the suggestion that they implement the service!

Your settings for all sites and applications can be found here.

On this page, if you click "Edit Settings," you can edit your settings for each specific application and site you have connected with including whether you want that site to always publish stories, ask you before publishing stories, or never publish stories for you.

When you "connect" your Facebook account to your account on another site, you can automatically see which friends of yours have already connected their accounts, and they can see you as well.

When your friend connects their Facebook account with an external site, they will be able to compare their Facebook Friend List with information from that website in order to invite more friends to connect. For example, if you use Digg.com with the same email info as your Facebook account, and your friend connects their account with Digg, they will be able to see the fact that you have a Digg account unless you check the box discussed below.

You can opt-out of being found on other sites by selecting "Don't allow friends to view my memberships on other websites through Facebook Connect" here.

If you have used Facebook Connect to connect your accounts to any sites, you will need to remove those sites here.

Please read the details here and on the Facebook Connect Page here.

Facebook Connect is available in 64 languages and locales. You can find more information in our Developer Blog post here.