Nuke Activity 0.1.0
Nuke Activity for Vanilla Forums
This plugin whipes every visual sign of the Activity feature away.
You can achieve that manually by setting the permission "Garden.Activity.View" to "false" and set the config value "Garden.Profile.ShowActivities" also to "false".
Super Admins in Vanilla always have all permissions and therefore it cannot hide the Activity page and links for super admins. You have to look at your forum as a guest or a normal user in order to see the effect.