Private Browsing prevents Safari from remembering which web pages you have visited and it also doesn’t collect Auto Fill information.
Sandboxing for websites
Stay protected against Malware and Malicious Code with built in website restrictions. Safari also runs web pages as separate processes which means if one tab/ browsing page crashes your whole browser doesn’t crash with it.
Intelligent Tracking Prevention
Have you noticed when browsing something online you see it later on as an ad? Safari removes advertisers access to track your online behaviors.