You can enable users to see a banner ad for announcements when they sign in to a Cisco Webex Meetings site.
From the customer view in https://admin.webex.com, go to Services, and under Meeting, select Sites.
Select the Webex site to change the settings for, and click Configure Site.
Under Common Settings, select Site Options.
In the Site Options section, uncheck the Display banner ad in My Webex check box.