Cross Post plugin for WordPress MU. Allows a post to appear in multiple blogs.

Allow a user to author a post accross multiple blogs in the same Multi-Site install.

WordPress to Posterous plugin.

Increase your Visibility and Blog Traffic. This plugin allows you to write a WordPress blog and cross-post it to your blog at BestThinking.com.

Automatically cross-post new WordPress content to Instagram, TikTok, LinkedIn, and more via your Fuxux account.

Auto publish your new and old blog content to Social Networks. Auto post to Twitter, Facebook, Linkedin, Pinterest, Blogger, Tumblr..