Update README.md

Author: kislyuk

README.md

@@ -1,5 +1,20 @@
 # xml-security.github.io
 
-This site hosts the documentation for projects in the XML-Security GitHub organization:
+This site hosts the documentation for projects in the [XML-Security](https://github.com/XML-Security) GitHub organization:
 
 * **[SignXML](https://xml-security.github.io/signxml/)**
+
+### Purpose of this project
+
+The [XML Security](https://github.com/XML-Security) project serves as a collaboration platform for developing implementations
+of security-related XML standards, including XML Signature, XAdES, and SAML, and sharing information about these XML standards.
+
+### Participating
+
+If you wish to become a member of the [XML Security](https://github.com/XML-Security) project, please open an issue in one of the
+repositories or email project members directly. Experts in the aforementioned security-related XML standards and active
+contributors to implementations are invited to join.
+
+If you wish to transfer a library or implementation that you maintain under this project, please open an issue
+or email project members directly. Open source libraries and implementations that are actively maintained are
+invited to join.