Social Group and the Permission Groups. What's the difference?

[matthewtelee]

After the vB4 update, I was browsing around my profile and I noticed two types of group, social group and permission group. Could someone please explain the difference.

 

[Rayne]

Social Groups are user created organizations that act like clubs on the forums. You're free to join whichever groups are open to your interests.

Permission Groups are what we use to designate specific permissions to a designated class of user (ie: unregistered user, regular user, provisional mods, etc. belong to different permission groups).

Permission groups were also used as part of an older system to designate who belonged to certain fangroups like Ash, Brock, Misty and Team Rocket and certain organizations like forum developers though it's not likely we will use this any longer since managing their permissions sometimes allowed unintentional loopholes in permissions for better or worse.