Sometimes I copy text from a formatted document, often a web page, and end up getting more than I bargained for. When I paste the text, I see that it has retained its source formatting. I hate this. I never ever want it.
No, I don’t want to start instant messaging in boldface just because tinyURL used a bold tag.
Where is the global-off-switch for this idiot feature?

You’ve hit upon one of my biggest pet peeves. Most instant messenger clients have this problem.
I also find that when using software like MS Word when you get that little popup on pasting “keep source formatting” “match destination formatting” not only highlights this problem… but makes it worse if you are doing multiple cut and pastes.
I wonder if there is some sort of universal clipboard replacement for Windows that could solve this
For OSX here is a good link to the same discussion on MacOSXHints. The comments people posted contain some good solutions.
http://www.macosxhints.com/article.php?story=20051213055833832
Thanks for the link Rob.
Since I posted this rant, I noticed that (on Windows) the same annoying “Match destination formatting” popup that I am bitching about has a “Defaults…” choice which allows me to turn it off (at least for MS Office apps).