Internet Explorer is a web browser developed by Microsoft that was the most widely used from 1999 to the early 2000s, though its market share has declined due to competition from other browsers like Google Chrome, Mozilla Firefox, Opera, Safari, and others. Internet Explorer security is important but can still be improved. These other browsers were designed with a focus on security, speed, and stability compared to existing browsers at the time of their development. They use various techniques like sandboxing and encryption to enhance security.