The simplest /follow addon for those too lazy to alt tab or help friends who are afking that you need to protect.
Unlike similar addons, this uses the AddonMessage channel, otherwise known as sync channels to broadcast to party members.
Follow me (the sender): /fm follow
Stop following me (the sender): /fm stay
Simple and straight forward. Perfect for leveling friends or alts. All players are required to have this addon to work.
Advanced:
With the newest version, out-of-party follow requests can now be done using:
Follow me (the sender): /fm blind follow receivername
Follow me (the sender): /fm blind stay receivername
Replace receivername with the player you want to follow you.
This is a niche case for those interested in pet-tagging leveling or in the cases of "I need to stay in this party/raid".