Used on the internet as an extreme form of /rage.
(there isn't supposed to be a space between the colon and the slashes, but urbandictionary is gay and won't "let me post links in the example". http: //rage)
Dude: HOLY SHIT I JUST DIED IN SKYRIM AND I DIDN'T SAVE!!!!11!!
Other dude: /rage, bro?
Dude: NO! (http: //rage)