msfreed

Thin Content Manager helps you easily identify thin content pages (i.e. posts and pages with minimal textual content) on your site and block them from search engines. The plugin calculates the body word count for each post/page on your site (disregarding words contained within HTML tags and shortcodes) and displays the information on a new ‘Thin Content Manager’ page within the Settings section of your WordPress admin panel. The admin page then provides a simple point-and-click interface to automatically insert robots noindex and nofollow tags – <meta name=”robots” content=”noindex, nofollow”> – into the head section of pages you select. These tags tell Google and other search engine spiders to ignore those pages, which is important for improving your site’s quality score and trust ranking for SEO purposes.
This plugin works with with single site installs only.

Thin Content Manager

See the body word count to identify pages with thin content, then select pages to insert robots noindex,nofollow tags into.

Eugen Bobrowski

Plugin provide to help search engines to indexing site correctly.
A simple plugin to manage your robots.txt. Plugin donn’t create the file or edit it. This plugin edit WordPress output of robots.txt content. And get you a easy and usable interface to manage it.
Features
<ul>
<li>Drag-n-drop robots.txt paths</li>
<li>Changing <code>blog_public</code> option form plugin settings page</li>
<li>Site map field for robots.txt</li>
<li>Robots.txt physical file checking.</li>
</ul>

Robots.txt rewrite

first review

Provide the easy managment of your robots.txt from admin side. It propose you the advanced then standard robots.txt content too.

Thin Content Manager vs Robots.txt rewrite