Wackbagger, Geek, Administrator
Wackbag Staff
From the developer of XenForo:

Kier said:
You may have noticed how the 'Reply' links on messages focus the quick reply editor, and pull in a quoted version of the message to which you are replying so that you can easily edit/trim your quote.
Kier said:
Have you also noticed however, that you are not limited to quoting a single message? You can click the 'reply' link on multiple messages and each of them will deliver their content to the quick reply box.

I say Multi-Quote (kinda) because at present this functionality is limited to messages on the same page, but I plan to allow this to operate across multiple pages in due course.