Because of its numerous benefits, most of the blogs would have the recent comment widget on their sidebar.
If you’re using the default recent comment widget, it’ll look like this.
The commenter’s name has a link back to his/her website (Yes, it’s a nofollow) and follow by the title of post.
For some reason, if you would like to disable the link on the name. Below is a simple method to do so.
1) Download (FTP) wp-includes/default-widgets.php to your local computer.
2) Open wp-includes/default-widgets.php with an editor.
3) Search for command get_comment_author_link() and replace it with get_comment_author().
4) Upload (FTP) the edited default-widgets.php to the web host overwriting the existing file.
Please note that, as this involves editing the WordPress core files, any WordPress update will overwrite your changes. Also this change might not be effective to those using a customized plugin widget to show the latest comments.