The latest mystery to capture the short attention span of the internet is ThatGirlEmily. It's a blog, supposedly written by "Emily" who during the past two weeks has discovered that her husband "Steven" is cheating on her. Coincidentally she started her blog just before all these interesting things in her life began occuring. Yesterday she decided to get even with Steven by placing a large billboard near where he works with this message on it: Emily's blog and billboard, as almost everyone who has posted about it agrees, just screams viral marketing. AtleastIhavechicken.com has summarized some of the reasons why it's probably a viral marketing campaign:
1) Emily has gone to some effort to conceal her identity;
2) Her blog is too well written (grammatically speaking) and the story unfolds a little too neatly to be real;
3) Since she started her blog, someone using the username ThatGirlEmily has been comment spamming numerous message boards. See here, and here, and here.
4) In addition to the billboard in New York (which seems to be real), an identical billboard has also been spotted in LA. The dual billboards, in my opinion, is the real clincher, because why would Emily, if she were real, pay for billboards in different cities?

I don't know who's the mastermind behind ThatGirlEmily, but here are the leading theories:

1) It's a viral created by an outdoor billboard company, to demonstrate the effectiveness of billboard advertising. (kind of like the Outhouse Springs campaign.)
2) Or it's a viral for a Court TV show. Possibly Parco P.I. (this is Gawker's favorite theory.)

Emily vows 14 days of vengeance. So I'm sure we'll eventually know the real story behind this.