This controls how many /invite commands can be sent for each room. Each room can send as many as the count as often as the seconds.
/as security set invite count 5
/as security set invite seconds 2
There are valid reasons for invites, but some people use them as a way to advertise their rooms. When the invite limit is exceeded, the invites will simply not be sent and the user will get an error message warning them not to mass advertise. If they try again a little later, the invite will go through.