Giving anonymous comments an author
Inspired by Morbus’s easy hack to give anonymous commenters a “[No Author]” name in the “Recent comments” box on the blog editing page, I decided to just name them “Anonymous” (which also gets rid of the rather strange “Posted by: on June 22, 2002” in the comment byline). In your mt directory, in lib/MT/App/Comments.pm, look for the line in sub post that reads “$comment->author($q->param(‘author’));” and change it to “$comment->author($q->param(‘author’) || ‘Anonymous’);”. Simple as that.
Updated for 2.2 : look for
$comment->author(remove_html(scalar $q->param('author')));
and change it to
$comment->author(remove_html(scalar $q->param('author')) || 'Anonymous');
Updated for 2.5 : same fix as 2.2.
Updated for 2.6: same fix as 2.2 and 2.5