A viral video is a clip that spreads very fast from person to person. A viral video, went viral, the viral video of the week.
The metaphor is exact, since spread depends on how many people each viewer passes it to, which is the same arithmetic as an infection. Nobody can reliably make a viral video, which is why agencies charge so much for trying.
viral video is a clip.
Practised in Music, Art & Culture, News & Communication