What is new in SharePoint 2013?
1. SharePoint 2013 provides a new way of working together and collaborating in the work place.
2. The Apps model with highly expanded CSOM (Client Side Object Model) and REST API. SharePoint 2013 is not only a product but also a development platform.
3. SharePoint 2013 style workflows (available in all versions except SharePoint foundation)
4. Claims and oAuth security(Claims is the default in SharePoint 2013, in SharePoint 2010 classic was the default, but in 2013 claims is the default. If you don’t go for claims, many of the features like Apps are not going to work for you.
5. Business Connectivity Service (BCS) enhancement to include Apps, external list improvements to provide functional parity with other SharePoint lists, and support for OData Business Data Connectivity (BDC) connections.
6. Web Content Management (WCM) has become cost effective and feature rich in SharePoint 2013.
7. Fast Search is integrated through and through into 2013
8. Micro Blogging Feature in SharePoint 2013
9. Shredded Storage by handling optimized SQL handling by updating only what is changed (i.e. delta)