VIRALITY
Виральность - характеристика контента, определяющая вероятность того, что пользователи смогут им заинтересоваться и поделиться с другими. На принципе виральности основан вирусный маркетинг.

The tendency of an image, video, or piece of information to be circulated rapidly and widely from one Internet user to another; the quality or fact of being viral.
The new speed-dating app took only three days to go viral.

If you make a video with yoga and cats, it’s sure to go viral.

The startup couldn’t handle its viral growth and almost folded as customers got annoyed at the web site failing to load.