I first heard this specific meaning of "bozo" during a talk to business students by one of Yahoo's founders.
A: "Get rid of the bozos. Seriously, fire them immediately."
2. n. Any old clown.
3. n. Annoying person.
4. n. A chat or message board troll.
5. n. A feature of About and Delphi Forums, and some other Prospero Technologies message boards that allows a moderator to surreptitiously silence a bozo (3).
6. v. To use the bozo feature on a message board; p.t., bozoed. Bozoed is also the adj. describing the condition of one subjected to the bozo feature.
Inspired by TV police dispatchers saying, "See the citizen at First and Main" when they would rather say, "See the bozo at first and main." Then applied to skiers, then to everyone.
Often shortened to BZ.
That bozo just cut me off!
That bozo stole my parking space!
Get out of the way, you bozo!
clown joker boor bumpkin buffoon