It's not a new meaning, and I don't think we can blame this one on Rush
Limbaugh. I agree with Jake here, and I too remember teachers handing out
dittos 40 years ago.
For U.K. and U.S. definitions. . .
The Compact Oxford English Dictionary
ditto
http://www.askoxford.com/
Merriam-Webster Online
Main Entry: 1dit·to
http://www.m-w.com/dictionary.htm
Sue
I think we have Rush Limbaugh to thank for the new meaning of ditto as a term of agreement. At least, that's how I now use the term even though, now that you brought it up, its original meaning was "of little importance." Funny how words begin taking a new life of their own thanks to a pop culture icon.