Sharepoint is another one of those impossible products to explain, and the simple reason for this is that its not so much a product as a platform on which codeless solutions are built. What makes it so incredible is that Sharepoint is now a standard feature in any Office 365 subscription.
Briefly, Sharepoint can be explained as an intranet; document management system; and team collaboration tool, amongst others. The reality is that SharePoint's use is largely determined by the solution designers imagination, and the specific needs of the business or organisation. The advent of The cloud and Office 365 have truly made this a platform that can no longer be ignored, due to its flexibility and power.