SP1 standardized high-level security for 128-bit encryption, which was vital for the growing trend of online banking and e-commerce.
This was the standout addition for general users, finally allowing them to see exactly how a webpage would look on paper before printing. Internet Explorer 5 5 Service Pack 1
This version was the final one to offer a "Compatibility Mode" that allowed users to run IE 4 side-by-side with IE 5.x for testing purposes. Performance and Developer Value Internet Explorer 5 5 Service Pack 1