Windows 98 was a popular operating system for PCs. The time when Windows 98 was released, Microsoft sold a lot of its copies. I think the integration of Explorer with Internet Explorer dedicated most to the success of Windows 98.
Under Windows 95, Explorer is a standalone program that only provides access to local objects or to LAN objects. Since Windows 98, Explorer is integrated with Internet Explorer. The change was not only the integration, but also many other features. Originally, the Start Menu of Windows 95 cannot be modified directly, and the menu items are always sorted. The user needs to open the start menu folder to modify it, and the user cannot have the menu items lay out in the way he/she prefers. Under Window 98, items can be dragged and dropped between Explorer windows and the start menu. Items in the Start Menu can be dragged to somewhere else in the Start Menu. With this feature the user can arrange menu items more easily. Originally, the address bar of Windows 95 Explorer is a dropdown list. Addresses cannot be typed. To go to an place, the user can only open the address bar and select an item. Under Windows 98, the user can type an address in the address bar and strike return to go to a place. With the Internet Explorer integration, the user can go to a place on the internet by typing the address in the address bar of either an Explorer window or an Internet Explorer window.
With the Internet Explorer integration, folders are browsed in a way like using the Internet Explorer. The user can go back or go forward when browsing. Also, the folders can be browsed in web view. With web view, pictures can be automatically previewed by Internet Explorer when selected. The user can customize Explorer to make it support "single click", a feature that allows the user to open a file using only a single click. The user can make the desktop more active. He/she can put web contents on the desktop as desktop items. The user can also use web contents as the wallpaper.
Internet Explorer 4.0 Setup can install Internet Explorer integration for Windows 95 or Windows NT 4 systems. To most Windows users, Internet Explorer integration brought much ease. On the other hand, Microsoft produced a buggy Internet Explorer so business users fear that their security cannot be guaranteed. Many viruses aimed to attack Microsoft Internet Explorer and its accessories, so it is seasonable to fear.