When somebody goes off topic to advance selfishly, such as advertising.
Person 1: Hey, did you hear Martha got pregnant?
Person 2: Awh, that's great news, anyways have you heard of my brand of almond milk?
Person 1: sheesh what a shameless plug.
by The7Guy April 13, 2021
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Same thing as Spam.

When somebody posts a single message on a message board advertising a product or website.
A shameless plug is the same thing as spam, dumbass.

Quit spamming and get a life.
by Drunky December 2, 2004
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