The Invisible power allows you to hide from lower ranks (i.e. owners can see other invisible owners, but owners cant see invisible main owners) at a chat you are at least owner and you will still be able to see the chat messages. The power automatically works while enabled.
If you send a message or perform any action on the chat your invisiblity will be broken and users will be able to see you again. To go back invisible sign out and in again.