Business grade solutions from Microsoft
The full Office 365 suite is comprised of a lot of different SASS products. However, the main thing people use are Sharepoint and Exchange online.
Exchange online combines world-class email with easy to use features and comes in a number of different packages. From Email only to the full office suite including Word, Excel and Powerpoint.
Sharepoint is an easy to use cloud file storage system that allows you to work offline, share files with your team or access them from anywhere in the world.