If you have an important announcement or wish to advertise a particular event you can set a banner to display at the top of the dashboard for all members on MMM. This banner will also appear at the top of any club kiosk screens you may have.
Go to the Banner tab of Manage clubs and type in your message. Then select an expiration date for when the banner should be removed. Banners are meant to be transient and not permanent so you can only show them for a limited time.
You can switch the banner off at any point be selecting "Banner will not be shown" in the drop down expiration prompt.
If you know HTML, you can put limited formatting of your text using HTML markup language.