Notes is a database program. Some links that describe NotesIts been around since 1987. The reason its been around so long is that it works better than systems costing 10 times as much.These links describe how powerful notes is.
What is Notes by Julian Robichaux http://www.nsftools.com/misc/WhatIsNotes.htm
Notes 9.0 vs Outlook 2013 IBM Slideshare presentation
Using Notes and Domino to present data via xPages. from Notes databases and SQL, to Web Browsers, notes clients and mobile, with the same code!!! xPages Home