"viral popularity" is correct and usable in written English.
You can use it to describe an internet trend that has become popular quickly and widely, often through sharing on social media. For example, "The dance challenge created by the singer quickly gained viral popularity among fans and was shared millions of times on social media."
It's viral popularity led to Biggs being interviewed on the BBC's Daily Politics TV programme.
"All lives matter" arose as "black lives matter" gained viral popularity and is viewed by many as an implicit rebuke to the movement.
Citing the viral popularity of "Donnie Darko," he said: "We're hoping with this to get kids turned on in a more political way.
The viral popularity of such numbers sparked a debate on how to define "mass shooting" – and whether crowdsourced counts were misleading.
While so-called urban brands like Phat Farm are not known for advertising in mainstream publications, preferring more of a "street gossip" or "viral" popularity, Def Jam University will take a broader approach.
Besides cornering the teen-idol market, Braun has established a reputation as the music industry's social-media maestro, skilled in the tricky art of converting viral popularity into more lasting mainstream stardom.
Of course, given the viral-internet popularity of a certain clip of The Beast - let's say - scratching his ears in the shower, he may never shower naked again.
This year's American champion is gif, short for graphics interchange format: one of the internet's oldest ways of transmitting pictures, it has undergone a viral resurgence in popularity as people rediscover how to post animated versions online.
One of my computer geek friends refers to it as "viral" because its popularity has spread so quickly.
Examples: "Life Hack" videos, "WonderHowTo" videos, etc. Viral Tip: For maximum popularity, you'll want to address problems that lots of people have a hard time dealing with.
The song quickly went viral, and its grass-roots popularity led to heavy rotation on radio stations across Sonora; before long, cellphone videos of people dancing to the song were flooding YouTube.
