At some point last year people started to realize that the email inbox was not only the “original” Internet social network, it’s also going to be the backbone of social networking going forward. You already have your friends (people in your address book), and the social graph is already filled (people you email, and who they email, etc.).
Yahoo is clearly focused on this, for example. And In December Plaxo bolted their social network, Pulse, onto Outlook. Now you could see what a friend was up to just before emailing them. Today they are rolling out the same functionality for the Mac Address Book.
Users must download a plugin that acts as a bridge between Mac’s sync services and your Plaxo account. This also sync’s your Mac address book with your Plaxo address book. In addition to basic contact data, Pulse will pull in recent friend actions on social networks (blogs, Digg, Twitter, delicious, Flickr, Yelp, etc.).
If you are a Pulse member, download the Mac client here.