So one of the things I’ve quickly seen with my WP MU experiment is that you need to be aware that  plugins are not all wordpress multisite plugin “safe”. However, more and more are safe to use in a WordPress 3 mulitisite setup (or network as it is called by WordPress documentation).

How To Check If a WordPress Plugin is Safe to Use With WordPress 3.x Multisite Installation

Some of the best ways to tell if a plugin is multisite safe are:

  1. Look up the  plugin on  WordPress.org and find the page dedicated to that plugin, then check to see:
    • If it is compatible with a pretty recent version of WP (look on the right-hand side)