Multisite
How to Activate a Plugin Automatically When Your Plugin is Activated
This tutorial explains how to programmatically activate another plugin when your plugin is activated in WordPress, including setup instructions, functions, and handling multisite environments.
Multisite Plugin Development: Essential Tips for Creating Multisite-Compatible WordPress Plugins
Multisite can be a complex topic, but I felt it would be worth it to go over Multisite from a plugin author's perspective. The result is a long-form article detailing Multisite in-depth.