What characteristic is essential for a successful online browser?

The essential characteristic for a successful online browser is speed and usability. A browser's primary function is to enable users to access and navigate the internet quickly and efficiently. Speed ensures that pages load rapidly, providing a smooth and frustration-free experience. Usability refers to how intuitive and user-friendly the interface is, allowing users to easily find and access the features they need, such as bookmarks, tab management, and settings.

When these two elements are prioritized, they significantly enhance the overall browsing experience. Users are more likely to stick with a browser that is not only fast but also easy to use, as it directly affects their productivity and satisfaction while online. In contrast, while cost-effectiveness, graphic design capabilities, and app compatibility are important factors in the overall technology ecosystem, they do not directly determine the core functionality of a browser in the same way that speed and usability do.