Lifestreaming on Facebook
"Rock Your Firefox" is more evidence of the viral eco-system being built on top of the foundations of Facebook. Not only do third parties get access to Facebook's millions of users, a key feature of the site is the lifestreaming of each user's online activities.
Before Facebook "opened" itself up to third party applications -- through the new Facebook platform -- a user's Facebook lifestream consisted only of internal activities on the site, such as adding a new friend or writing on somebody's comment wall. However, with the addition of new Facebook apps, activities aggregated from elsewhere on the web can now be part of a user's profile. So for example, music listened to through iLike or micro-blog entries on Twitter, can be featured. And with "Rock Your Firefox" this can now also include installing a new Firefox add-on. Not only is Facebook making lifestreaming mainstream, but it also gives companies a very viral and social platform from which to promote their wares.
The downside (and upside depending on your privacy concerns) is that access to a user's Facebook lifestream is only possible if logged into Facebook, and if you have certain profile privileges. What Facebook needs to do to make the site the ultimate lifestreaming service is to enable users to have even finer control over who can access their Facebook activity data, including the ability to make it completely public -- perhaps through RSS or an embedible widget. This of course would be an about-turn from its current strategy, where data can flow in, but can't easily flow out of the site. As many have noted, Facebook isn't really that open at all.