When you dominate someone, you can choose to add them to your Hive Mind, joining them with your stream of consciousness. This gives your Hive Mind perfect control over them, and causes any effects from domination to last forever instead of degrading. You may undo this at any time.
Power Assimilation
When you assimilate someone, their powers are assimilated as well, allowing everyone in the hive mind access to them at the same time.