Brad Williams

This plugin lets you create category mappings allowing for one top-level blog to act as a portal for your global community of WPMU blogs. Category postings are aggregated based on the mappings and displayed on the top-level blog.
Features:
<pre><code>* Map multiple top-level categories
* Built-in sidebar widget to display all categories
* WordPress MU 2.7 approved!
</code></pre>
<h3>Plugin Support</h3>
<a href="http://webdevstudios.com/support/wordpress-plugins/" title="WordPress Plugins and Support" rel="nofollow ugc">WordPress MU Category Mapping Plugin</a>

WordPress MU Category Mapping Plugin

Plugin links categories network wide to provide one top-level blog to act as a portal for your global community of blogs

sharespring

ShareSpring is a service that finds great user-generated content and embeds a beautiful gallery of the best posts onto your website.
Search for posts on Twitter, Instagram, Facebook, YouTube, and RSS. Pick which posts to embed on your website.
Display your own posts from all of your social networks, or find public posts, or mix everything together.

WordPress MU Category Mapping Plugin vs ShareSpring