copperblade

Update: If you need more functionality please see the next generation of this plugin at https://wordpress.org/extend/plugins/network-latest-posts/
Creates a widget to show a list of the most recent posts across a WordPress MU installation. It shows the most recent post from each blog. This plugin is based on the work of many authors.
This works on previous versions of WPMU, but not on previous versions of WordPress (where it doesn’t make sense).
<h3>Options</h3>
<ul>
<li>Number of posts to show – list this many posts.</li>
<li>Number of days to limit – only go back this number of days to get posts. Set to -1 for no limit (default).</li>
</ul>

Multisite Recent Posts Widget

Creates a widget to show a list of the most recent posts across a WordPress MU installation.  It shows the most recent post from each blog.

Ron Rennick

The functionality in this plugin was incorporated into the built in export feature in WordPress 3.0
Working with a single large export file can be difficult. Use this plugin to create multiple export files that contain sections of your blog. This plugin has been tested on WP & WPMU versions 2.7 – 2.8.4. The plugin may work on earlier versions of WP/WPMU.
All restriction options provided in the plugin are optional. If no restrictions are selected, this plugin generates the same export file as the export feature built into WP & WPMU.
Features
Export by any optional combination of:
<ul>
<li>Date Range – Start & end month/year</li>
<li>Author – Same as WP/WPMU built-in export</li>
<li>Category – Export a specific category</li>
<li>Content type – Choose either posts or pages</li>
<li>Post status – Choose Draft, Published, Scheduled or Private</li>
<li>Blog Tag/Category Terms – Choose whether to include the blog’s complete list of Tags and/or Categories</li>
</ul>
Support can be obtained through:
<a href="https://wordpress.org/tags/advanced-export-for-wp-wpmu?forum_id=10#postform" rel="ugc">WordPress Forums</a>

Advanced Export for WP & WPMU

Adds an Advanced Export to the Tools menu which allows selective exporting of pages, posts, specific categories and/or post statuses by date.

Multisite Recent Posts Widget vs Advanced Export for WP & WPMU