This is an example of reverberation of an idea or advertisement – it has a lasting impact, it generates ads of a similar nature, and it becomes embedded in our culture.

It is not, however, viral by any means. It did not spread peer to peer starting at a small “infection” point. It did not grow exponentially through people sharing it because they thought it was interesting.

It reverberated, but it was not viral.
Interchanging one term for the other will give an inaccurate picture.

They neither grows exponentially nor spread peer to peer. Those are the essential characteristics of viral marketing.

What you are describing is any marketing which is “effective”, or “persistent”, not which “spreads itself through the mechanisms of peer interaction” and “grows larger exponentially through natural communication”.

imo

Reverberate; To have a prolonged or continuing effect
Example: Those talks with his teacher reverberated throughout his life.

An echo dies down. That is true. That is why I’m not talking about Echo Marketing Reverberating is stronger.

The reverberation cannot be louder than the original noise.
It does not grow before dying off.
It does not imply spreading from person to person.

The term viral is used and popular because it describes what happens: it spreads peer to peer without additional input. It grows the number of people using or viewing it organically. It spreads exponentially as more people take it up.

Reverberate does not imply any of these things.