Obscure reference to the Simpsons: Monty Burns has just made a speech, and was getting booed out. When he asks his kiss-ass assistant if they're booing him, he replies "No, sir...they're saying boo-urns." He then asks the crowd, and they continue to boo him, save for Hans Moleman, who says "Well, I was saying boo-urns."

An exclamation, used in disappointment or excitement

A swimmer

Similar to "boo," only not quite the same.

Similar in meaning to the more conventional "boo", but with more emphasis. For the avid Simpson viewer in particular.

Exclamation. A cheer for The Simpsons character Montgomery Burns. Often used incorrectly by Canadians to suggest disproval of anything, rather than approval of Burns.
Obviously, "boo" and "Boo-urns" are two different and mutually exclusive words.

PRAISE for something

....NOT the same as "boo"

otherwise that line in the Simpsons doesnt make any sense

Boourns is not similar at all to boo, it is in fact the opposite of booing.

It comes from an episode of The Simpsons when Mr. Burns made a film for a film festival that no one in the audience liked, so they booed him. Burns, being surrounded by yes-men for his whole life was unfamiliar with being booed so Smithers told him they were chanting "boourns" rather than booing.

Mr. Burns stood up and asked the audience if they were booing or if they were chanting boourns. They responded by booing him, except for Hans Moleman who admitted to chanting "boourns" which leads one to the conclusion that Moleman liked the movie and was using the expression to show his enjoyment.