Having your website mentioned by a social actor so viral that it makes your servers crash. The expression originates from comments regarding Matthew Inman's (cartoonist behind The Oatmeal) sending a gigantic amount of people on a given website once he mentions it on his facebook page, and making this website unavailable to other fans within seconds of being posted, every single time.
— Heh. Their site's been oatmealed.
— I know, they'll need a new server now that The Oatmeal mentioned them in a post!
— It kinda both is nice and sucks to be oatmealed.