Ironically, there's a pretty good chance that the state in the image (Petrov as well known as Justin Bieber) will probably happen not when Petrov becomes well known, but because Justin Bieber becomes relatively obscure. How many people here recognize the name Jennifer Rush?
Nitpick: the image might work better if it stated more clearly what Petrov did to save the day.
Agreed. Also the link to the LW article seems to have little point, being part of the image and not clickable or copy-pasteable. How many people would take the trouble to write it down, rather than just googling Petrov if they are curious? Maybe you could replace it by "For more information, google 'Petrov Day Less Wrong' " if you want to make sure they see Eliezer's post.
9/26 is Petrov Day
While mentioning this in Facebook statuses, Tweets, and face-to-face conversation is good, things often stick better when there's a picture associated with them. Image macros are popular, and more fun to share. So here's one for Petrov Day I threw together.
http://i.imgur.com/3GNms.jpg