It was discussed here before
As yet the exact identity of this viral remains a mystery. The website thisman.org claims that hundreds of people from around the world have seen this face in their dreams.
The website is registered to a marketing firm renowned for its unconventional advertising, so expect something to develop soon.
Internet speculation leans towards this being related to a new Nightmare on Elm Street movie (hence the dream link). If that's the case the advert is following in the footsteps of Snakes on a Plane and The Blair Witch Project, which both used the internet to create a following before the movies were released.
MSN News
http://thisman.org/