Update README.md

Author: Michael Davis

README.md

@@ -4,12 +4,24 @@ A JOSE implementation in Python
 
 [![Build Status](https://travis-ci.org/mpdavis/python-jose.svg?branch=master)](https://travis-ci.org/mpdavis/python-jose) [![Coverage Status](https://coveralls.io/repos/mpdavis/python-jose/badge.svg)](https://coveralls.io/r/mpdavis/python-jose)
 
+The JavaScript Object Signing and Encryption (JOSE) technologies -
+JSON Web Signature (JWS), JSON Web Encryption (JWE), JSON Web Key
+(JWK), and JSON Web Algorithms (JWA) - collectively can be used to
+encrypt and/or sign content using a variety of algorithms.  While the
+full set of permutations is extremely large, and might be daunting to
+some, it is expected that most applications will only use a small set
+of algorithms to meet their needs.
+
 ## Principles
 
 This is a JOSE implementation that is meant to be simple to use, both on and off of AppEngine.
 
 ## Examples
 
+### JSON Web Signature
+
+JSON Web Signatures (JWS) are used to digitally sign a JSON encoded object and represent it as a compact URL-safe string.
+
 #### Signing tokens
 
 ```python
@@ -25,6 +37,11 @@ This is a JOSE implementation that is meant to be simple to use, both on and off
 {'a': 'b'}
 ```
 
+### JSON Web Token
+
+JSON Web Tokens are a JWS with a set of reserved claims to be used in a standardized manner.
+
+
 ## Algorithms
 
 The following algorithms are currently supported.