what is foo?
 

hi,

what is 'foo'?

ashlesha.

Foo is a mystical substance of the computing world. Foo makes all programs work and is offset by its counterpart, bar. Foo-bar is the yin-yang of the computing world.

Seriously, 'foo' is a term used for a sample variable, intended to indicate that it has no particular meaning, a metasyntatic variable.

http://en.wikipedia.org/wiki/Metasyntactic_variable

aah!
thank you--
a

Some people also use it to say F*cked up beyond all repair.

^^ that's fubar not foo-bar :P

foobar actually comes from fubar (homonyms, I believe the term is)