Microsoft Office is a suite of applications including Word, Excel, PowerPoint, and Outlook. It was first released in 1988 and bundled Word, Excel, and PowerPoint. Over time, Office applications have integrated shared features like a common spell checker. Office is used by over a billion people worldwide and allows third-party developers to create add-ins. The Office suite is available on desktop and mobile devices, and also includes server applications like SharePoint, Project Server, and Lync Server.