Sharepoint Online
SharePoint Online is a powerful component of Office 365, which provides companies with the ability to create intranets, extranets and unique collaboration solutions.
SharePoint Online offers all the powerful features of SharePoint, preventing the overload that results in local management of the infrastructure.
SharePoint can be purchased as a standalone product or as part of the Office 365 suite.
In this case you also get access to Exchange, Lync, Office clients and the Office web apps.