What is the term for a computer network system used to share information on the World Wide Web?

The term that describes a computer network system used to share information on the World Wide Web is the Internet. The Internet is a vast network of interconnected computers globally that allows for the exchange of data and access to resources. It serves as the underlying infrastructure that supports various services, including the World Wide Web, email, file sharing, and more.

The other options do have their specific meanings but do not encompass the broader concept of a global network. A data network typically refers to a group of interconnected computers within a smaller environment, like a local area network (LAN). A web portal is a specific web-based interface that provides access to a variety of resources or information, while an online database refers to a structured collection of data that can be accessed through the Internet. Therefore, while these terms relate to aspects of networking and web usage, the Internet itself is the comprehensive system that facilitates sharing information on the World Wide Web.