Abbas S

This plugin helps to create a widget and shortcode to create featured blogs.
Following are the things done
A settings page created for featured. 
You can enter the blog id in the blog id: text box in the settings page and click on get blog details button . 
This will fetch( by AJAX ) get the blog name , blog link , and blog Avatar ( based on the avatars plugin ). 
It will also add two buttons 
 Add this blog -> Which will add this blog to the featured blog list 
Can -> it will not add the blog to the featured blog list. 
Then saving the settings will save it. The settings are saved different for each blog . 
Then the user can use the widget as follows . 
Drag the widget on a widgetize area. 
Enter the blogids in the widget , then those blogs will be used as featured blogs. 
If nothing is entered in the bloglist the blog list from the settings will be taken. 
The user can use the short code as follows
The user can specify the blog list in short code argument. For e.g:- [multisite_featured_blogs blogids=”3,2″].The those blogs will be displayed in the featured blog list. 
If the user passes no argument then in case the featured blog list will be taken from the settings. For e.g:- [multisite_featured_blogs]
This plugin was done as a part of some work done for http://premium.wpmudev.org/ , but was later not released. 
Thanks for all the help for this plugin from WPMU Dev

Multisite Featured Blog

This plugin helps to create a widget and shortcode to create featured blogs

Boone Gorges

Mariusooms

reblevins

Requires BuddyPress 1.7+ and PHP 5.3+.
The BuddyPress Groupblog plugin extends the group functionality by enabling each group to have a single blog associated with it. Group members are automatically added to the blog and will have blog roles as set by the groupblog admin settings.
Features:
<ul>
<li>P2 integration and frontend posting.</li>
<li>Admin can set Template specific groupblogs.</li>
<li>Allow group admins choose the desired template page themselves.</li>
<li>Full blog theme integration. The included bp-groupblog theme mimics the group pages.</li>
<li>Automated blog registration at group creation stage.</li>
<li>Bypass default blog validation to allow dashes, underscores, numeral only and minimum character count.</li>
<li>Blog privacy settings are initially inherited from group privacy settings.</li>
<li>Group members are automatically added to the blog.</li>
<li>Blog roles match group roles as set by the group admin.</li>
<li>Solid error checking that the blog follows validation.</li>
<li>Group admin tab to access the group-blog settings.</li>
<li>Blog themes will have the ability to pull in group info and create a theme that could resemble the group exactly.</li>
<li>Leaving the group will downgrade the member role to ‘subscriber’.</li>
<li>Allow the group admin to select one of his/her existing blogs.</li>
<li>A new ajax backend.</li>
</ul>

BuddyPress Groupblog

BuddyPress Groupblog extends the group functionality by enabling the group to have a single blog associated with it.

Multisite Featured Blog vs BuddyPress Groupblog