After the update to Mavericks (10.9), anything copied from Terminal is pasted in the target app with the same formatting as in Terminal, in my case, white monospaced letters on a black background, e.g.:
(I pasted some text from Terminal into a New Mail window.)
Previously (10.8 and earlier) only plain text was copied, without any formatting at all.
This happens in apps that are capable of receiving rich text formatting. In plain text apps, e.g. TextWrangler or TextEdit in plain text mode, only the content is copied, of course.
Can formatting copying be disabled for the Terminal app?
The same happens in Yosemite (10.10) and El Capitan (10.11) as well.