Facebook has opened up its website to external e-mail addresses. A pretty bold move by the company that is completely closed off. Now you can not only send your facebook buddies an email, but also add in external email addresses to chime in on the threads.
This is a great move by the growing social networking company that has already been on a tear lately. They have added such great features as of late and all the good that has become of opening their API.The move now allows users to possibly in the future use facebook as their one stop spot for keeping in touch with friends, family, etc.
Overall, I think facebook has been making some good calls lately and this just adds to it.