The script adds a 'Reply' link in the footer (after the date), which adds all the contents of the comment's body to the comment form. <BR> tags are converted to line breaks, and quoted lines are enclosed in <i> tags with a rel attribute of 'cquote' for easy styling (Blogger doesn't allow 'class' attribute in comment elements). The text is wrapped in “curly quotes”.

Script also adds a 'Return' link right above the comment body input area, to quickly return to the comment you came from.

Update: Added author's name in comment, so quoted comment looks like -- "Author: comment"