Facebook announced this month a new set of website plugin features called Social Plugins .
These let you integrate Facebook into your own websites. The set includes a 'Like' button that lets Facebook users post a like event into their profile, straight from your website. You can see one in action at the end of this news item.
The concept is similar to the current social bookmarking systems. However it links bookmarking with the most powerful social networking website. Being liked will put your website in front of a network of friends with similar interests.
This has caused quite a stir, from privacy issues to speculation that it may be the death of Google.
I don't believe it will change the world, but it does introduces a new way to socially promote your business.