I installed this but found a problem with markdown. The plugin seems to assume Markdown is installed but this may not be the case.
Fatal error: Call to undefined function: markdown() in /home/eduo/public_html/wp-content/plugins/yet-another-related-posts-plugin/yarpp.php on line 68
I'm not sure if it's common to have it installed but I don't have it. Testing for the markdown function before might be a good idea.