Hi,
Viral Marketing is that which is able to generate interest and the potential sale of a brand or product through messages that spread like a virus, in other words, quickly, and from person to person. The idea is for it to be the users themselves that choose to share the content.
Due to their speed and ease to share, social networks are the natural habitat of this kind of marketing. The most widespread example in recent times is the creation of moving, surprising or spectacular videos on YouTube, which are then shared on Facebook, Twitter and other channels.