Achievements is a feature which awards points and badges for various editing tasks.
The theory is that by rewarding users, this encourages editing; but many admins have found that in practice, achievements mostly encourage trivial editing for the sake of racking up the points, or in extreme cases, vandal editing.
How to disable itEdit
For a wiki, admins can enable/disable Achievements by a setting on the Wiki Features subpage of the General tab of the Admin Dashboard page. Individual users can also opt-out of Achievements by a setting in their personal preferences.