Verb. Sending a tweet or tweeting @someone more famous than yourself in hopes that they will re-tweet and make you famous for a few minutes in the twitter-verse. Opposite of 'down tweet' or "down tweeting".
the number 5000. originally referring to points, "dolphins" have grown to include just about anything.
origins: the online game Robot Unicorn Attack, where every 5000 points you get, another dolphin joins the pack.