SharePoint 2013: What is new in Manage Property and Crawl Property

• Automatically created when site column created and used (the must be stored in the content database using this column).
• Crawl properties now crated at the site collection level. Earlier only available at the application level.
• Crawl properties & manage properties created with specific naming convention, as mentioned in the attached link MSDN.
• Automatically created crawl properties sortable and refinable are turned off and property with text data type.
• There are list of OOB Manage Properties available at site collection level with different-2 data type start with name Refinable<datatype>00 .. Refinable<datatype>100 to you can use this to make achieve Sorting and refinable by map crawl property one of manage property give it alias. 

• There is confusion with crawl property, actually in SharePoint 2013 two crawl property created when ever a new site column created and it used. I have created the site column name "MyCustomDate". SharePoint 2013 two crawl properties created "OWS_MyCustomDate" and Other "ows_q_DATE_MycustomDate".

Ref:

http://blogs.technet.com/b/speschka/archive/2013/04/04/creating-refinable-and-sortable-managed-properties-in-sites-and-site-collections-in-sharepoint-2013.aspx

http://sharepointfieldnotes.blogspot.in/2013/05/understanding-and-getting-sharepoint.html

http://sharepointfieldnotes.blogspot.in/2013/08/how-to-turn-off-auto-generated-managed.html