In order to support the ECM (enterprise content management) we decided to publish the new features accessible in SharePoint 2013.
Publishing site development through basic client program models
The users are now free to use CSOM (client object model) as well as Java script, Silverlight etc. All site components, elements and know behavior is still intact.
SharePoint application models for taxonomy and applications
Specialists are now free to write any kind of client code as well as server code in applications of SharePoint 2013. The user interface will still be totally functional.
Design, branding and authoring
The whole set of brand new features for .NET development are now accessible in SharePoint. They are considered for design, author, brand, site extension etc.