He implies that it’s a prank, but doesn’t provide details. Stay tuned, I guess.
There is already a “NSFW.com” website (it’s NSFW, obviously), and it doesn’t appear to be owned by Drew Curtis.
My first guess was that Curtis was planning some sort of boobies-related enterprise using the NSFW acronym, and with the trademark application was trying to make sure no one beat him to the punch. But that a NSFW.com already exists, and has since 2000, makes me think this may well be a prank, or some sort of exercise in showing the absurdity of trademark law. I can’t think any lawyer would’ve told him he’d actually have a shot at securing the trademark.