*** PLUGIN DEVELOPMENT ABANDONED – It is no longer useful and/or compatible with recent versions of WPMU or WP >= 3.0 ***
Mu-ABS (which stands for Mu Automatic Blog Subscription) is a mu-plugin for WordPress Mu.
When you build a blog network with such a platform, you probably wish that a user subscribed to one of your blogs is actually subscribed to each blog of the network. This does not natively happen with WordPress Mu.
This mu-plugin changes this behavior. When logged-in users visits a blog for which they have no capabilities (i.e. not subscriber), they are automatically and transparently added as a subscriber.
GNU General Public License v3
2008-09-09 – Release 0.1
2008-09-09 – Changed the subscription event: on visiting the blog instead of accessing the user profile
2008-08-12 – Picked up the idea from https://mu.wordpress.org/forums/topic.php?id=6785#post-40426