Small does not mean useless. The phrase was suited to this small module: Comment Fragment. Drupal.org using this module to rewrite the comment permalink.
The default Drupal 7 comment permalink has the following format,
/comment/[comment-id]#[comment-id], if a node has 10 comments, each page with the URL
/comment/[comment-id]loads identical content to the node itself.
Besides, the bot will crawl those comments pages like crazy and adds unneeded load to our server.
The solutions is by installing Comment Fragment. It rewrite the comment URL format to
/[node-alias]#[comment-id] and than redirect the old URL format to new one.
Remember if this module only rewrite the comment permalink generated by core comment module. Comments generated by e.g Views module not changed but redirected to proper URLs.