New Facebook E-Mail Reply Feature

The caption below is an example of a new feature recently added to Facebook:

New Feature: Reply to this email to comment on this photo.

To see the comment thread, follow the link below:
http://www.facebook.com/n/?photo.php&pid=73845693&id=1299573645&mid=4FDD234234GEADFGA

Thanks,
The Facebook Team

In short, this new feature enables the user to reply to a post via e-mail if the post was originally sent to the user via e-mail.  This is convenient if the user is on a cell phone and it's cumbersome --or not possible-- to launch a mobile web browser on the phone to reply to the post.

This seems to be just the "digital glue" that Greg Cangialosi speaks of in the presentation below:

View more presentations from Greg Cangialosi.

This begs the question.... Is e-mail dead or is it simply taking on a new role in the context of social media?