To be fair, their meaningless is their value. Using "real world" names may distract from the logic being discussed or unreasonably suggest that the logic may fit only a particular scenario.

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

Perhaps reading RFC 3092 - Etymology of "Foo"[1] might be helpful.

Personally, I was familiar with the acronym FUBAR first, so it comes as natural to me as most mainstream, American acronyms.

[1]http://www.faqs.org/rfcs/rfc3092.html