going viral 

An idea, concept, product, video or other cultural meme exponentially increases in popularity, meaning its popularity doubles every minute, hour, day, month or other unit of time.

On youtube increasing popularity can be tracked by clicking the video statistics icon to the right of the number of times viewed.

The 'Miracle - Matisyahu Hanukkah' video is now going viral. It's a viral video. It's popularity is doubling everyday (as of 12/03/2010, eventually it will plateau).

going viral by Meme-ologist December 4, 2010

Worth going viral 

When something someone says or does is so magnificently stupid or outrageous that you can imagine it being spread all over the internet in a matter of hours.

"Did you hear what Tom said in his best man speech?! That was so worth going viral!"

Worth going viral by Kentoonist June 16, 2013