Are you seriously pretending viral marketing isn't a real thing?
Viral marketing is a corporate entity creating an object that is then adopted and distributed by consumers. What it is NOT is spontaneous reaction to material like a movie that then is captured and distributed by consumers themselves. Using the term viral marketing implies that HBO or the producers worked with fans to fake the "reaction" videos and all the outrageous comments on Twitter on other social media, hence a "conspiracy" to further the popularity of the show and bring in more viewers by an orchestrated effort.
Sometimes a fuck is just a fuck, and a reaction is just a reaction, and not some corporate media scheme to drum up more viewership. The red wedding isn't some secret and nobody knew what was going to happen. Tons of people knew what was going to go down (and plenty of viewers who have only seen the series didn't), and knew people would be going "Oh WTF??" when it happened.
But hey, go on thinking it was a scheme by the corporate overlords to milk more money out of the dumb shmucks by creating a "viral marketing campaign" out of it. Personally, I think you give them WAY too much credit and I'm certain they WISH that they could create a campaign like this one on purpose. How's that tinfoil hat fitting? (Ozin quoted, but obviously directed at Tot.)