From NBC's public service advertisements. During the short clip a celebrity personality will state some fact, followed by the ending "The More You Know" sequence.

Can be used as a sarcastic response to learning some typically useless knowledge, trivia or fact.
Bill: Its recommended to drink 6 glasses of water a day
Me: "The more you know"
by J. Ev. March 6, 2008
A reference to NBC public service announcements which would feature celebrities reciting a random (usually touching) fact, followed by the statement, "The More You Know."

Thus, a person may say this after reciting something that is not necessarily useful to the listener. It may also indicate that the user does not expect a response from the listener.

Often rendered like a tag, e.g. #themoreyouknow.
Phil: Sup dude?
Bryan: chilling.
Bryan: brb, gotta poop
Bryan: The more you know.
Phil: ...
by IAmLordDumbledore February 8, 2011