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

BjornW

<blockquote>
THIS PLUGIN IS NOT MAINTAINED ANYMORE! 
 For historical purposes this plugin is still online. The general concept could still be useful, 
 the code is probably not working and horrible outdated.
</blockquote>
Create streams of sitewide aggregated content from your multisite WordPress installation with bbAggregate.
A stream contains posts from those blogs allowed to participate in the stream. Anyone writing posts can add his/her post to one or more streams. 
The streams are shown by using a specific page template. (see also the examples directory). It offers functionality similar 
to the sitewide categories / global terms, but with more control and (hopefully) less buggy behaviour.
This plugin adds two database tables to your installation:
<ul>
<li>$prefix_bbAggregate_item (links an item to a stream)</li>
<li>$prefix_bbAggregate_stream (contains the stream info) </li>
</ul>
NB: This plugin is only useful for a WordPress Multisite installation in which multiple 
blogs are being used.
<h4>How does it work?</h4>
First, you create a stream (neccessary user capabillity: ‘manage_options’,admin role works perfectly). (See screenshot-4.png) 
It is recommended to only use letters, numbers and underscores or dashes in the stream name. Spaces in the name may cause problems at the moment.
Streams are defined by a name, a description (which is saved but not yet accessible for public use) and some options (see screenshot-5.png) such as:
<ul>
<li>maximum number of posts (limits the total amount of posts in a stream)</li>
<li>maximum number of posts per blog (limits the amount of posts per blog in a stream)</li>
<li>number of posts per page (limits the amount of posts per page. Pagination is included)</li>
<li>excluded blogs (blogs which have been explicitly excluded from using this stream. Posts from these blogs will not be shown in this stream) </li>
</ul>
After creating a stream (See screenshot-6.png and screenshot-7.png), create a post in a blog which is not excluded from this stream. Below the Post Editing Area you will see a new metabox called 
Streams (see screenshot-8.png) with a list of available streams (streams which have excluded this blog are not shown). By ticking the checkbox in front of the stream name 
you’ve added your post to this stream. Every user able to add a post may add his/her posts to the streams shown.
To show a stream of content you (or the theme designer of the theme you use) need to prepare the theme for showing the items. You need a page template 
for this. An example of this can be found in bbAggregate/examples and the template is called: bbAggregate-template-aggregated-posts. For now you can copy 
it into the directory of your active theme so you can test bbAggregated. Keep in mind though that it will not use your theme’s style! 
Create a page in the blog where you also have copied the page template and select the Aggregated Posts template 
as the page’s template. Add the customfield with the name ‘bbagg_stream’ (without quotes) and customfield value the exact(!) stream name of the stream you want to show (see screenshot-11.png). 
By the way, the example page template the custom field name is hardcoded, but you can change it in the template as long as you also use the new name 
for your customfield. After adding the customfield name and value and publishing the page you can view the page and you should now see your post part 
of the stream’s aggregated content (see screenshot-12.png).
Note: The stream default options can be changed sitewide by visiting the Super Admin->Options (See screenshot-9.png). Look for ‘bbAggregate sitewide defaults’ (see screenshot-10.png). After changing 
the options’ values and saving the changes new streams will use your new defaults. This can only be done by users with super admin rights. Keep in mind that streams are sitewide. Thus streams created in blog 1 
are also visible in the bbAggregate settings of blog 2.
<h3>TODO</h3>
Feel free to send patches 😉
<ul>
<li>Remove database tables upon delete of plugin </li>
<li>Add .po and .mo files for translations</li>
<li>Create php doc files</li>
</ul>

bbAggregate

Create streams of sitewide aggregated content from your multisite WordPress installation with bbAggregate

WordPress MU Category Mapping Plugin vs bbAggregate