If you drag an article from NetNewsWire to Adium your formatting will be changed to whatever font was brought over from NetNewsWire. If you click inside the text entry field after dragging the article over then your formatting will be changed to whatever formatting the cursor is currently in. If you click on the window's titlebar and then hit enter to send while the text in the input window is selected then your formatting will be set to the same formatting as a link.
The screenshot below shows the behavior I'm talking about. The first link was dragged from OmniWeb and shows that formatting was properly reset. The second link was dragged over from NetNewsWire, and then I clicked in the text entry field and hit enter. The next line was typed without applying any formatting. The third link was dragged over from NetNewsWire and the window was brought forward by clicking on the titlebar, then clicking enter. The line after was typed without applying any formatting. That last line is not actually a link, just has the formatting for the link.
http://darkstar.frop.org/~zwhite/Adium-bug-formatting.jpg
This should be easily reproducible using Adium 0.84. I'm using OSX 10.3.9 with all Security Updates applied as of 2005 Oct 1.
