Starting in January 2015, Microsoft is making changes to the SharePoint Online Public Website feature. Customers who currently use this feature will continue to have access to the feature for a minimum of two years following the changeover date. New customers who subscribe to Office 365 after the changeover date won’t have access to this feature. Moving forward, Office 365 customers will have access to third-party offerings that will enable them to easily integrate their public presence with their Office 365 service. Additional details about these solutions will be made available in January 2015.
Read more at http://support2.microsoft.com/kb/3027254