What does a virus mean?

There's a viral message on the Internet There's a saying.

I don't know what it means even if I search in advance.

What is the meaning of the virus here?

5555 2019-06-26 Gentleman

Literally, it means word-of-mouth marketing
It's not about advertising, it's about people spreading word of mouth to each other

Gentleman 6 years ago 0

It's word of mouth, but these days, companies purposely make word of mouth

Gentleman 6 years ago 0

Usually, when you use a virus on the internet, it's when you use a sponsor on your blog or Instagram to promote it

Lady 6 years ago 0

Is this spelled viral? That's what the dictionary says

Gentleman 6 years ago 0

That's right
I use it because it spreads like a virus

Gentleman 6 years ago 0

Thank you all!

Gentleman 6 years ago 0