AuditySEO Canonical Manager

Choose reliable automatic canonical URLs or set a preferred URL for individual posts, pages, and public post types.

The Copyscape Premium plugin lets you check if a WordPress post is unique before it's published, by searching for duplicate content on the web.

Makes it easy to pull content from one post or page and place it on another using a simple shortcode, even in a multisite environment.

Duplicate content cure is a simple plugin that improves SEO by preventing search engines from indexing pages that contain duplicate content.

Replytocom Controller lets remove "?replytocom" from comment reply urls and redirect bots who try to use it anyway.

Checks your contents (posts and pages) against the web for inadvertant duplicate content before postings. Detects online copies of your older posts.