Since 2003 Safari has been Apple's default Mac web browser. The browser was based on Apple's own internal version of KHTML, a free software web page rendering engine. The underlying WebKit technology Apple's developed has gone on to power other browsers too. Safari sports integration with iCloud, Apple's cloud service, with features including Shared Links, making it easy to view content friends and colleagues have shared via social networks. Advanced power saving technology helps Safari spare your MacBook battery from draining when it encounters web pages that use power-hungry technology like Adobe Flash. Safari is also outfitted with advanced privacy and phishing protection, and also supports extensions, enabling third party to developers to create new features and functionality.