Mark

http://www.hatshoe.org/mark.html

Contents:
"I woke up and they had left a mark on me. It looks like this:



I don't know what it does yet.

(Not this part. These words aren't part of the mark.)

Clues:
HTML notes: @live.com

and to enter, use the missing of the three.

Additive, mostly used for digital.

Clues: The note could mean something. Perhaps an MSN username. It's worth looking into.

The mark could mean something important. Maybe worth looking into?

The Mark is shown (mirrored) in the video "N" at around 0:18

Chain: [nothing]