* It's a proper noun: "World Wide Web" is the specific name of the global network of computers. Just like we capitalize "United States" or "Amazon River," we capitalize the unique name of the internet.
* Common usage: This is the standard practice in most writing styles, including journalism, academic writing, and technical documentation.
Examples:
* The World Wide Web is a powerful tool.
* I learned about the history of the World Wide Web in class.
* The future of the World Wide Web is exciting.
However, if you're referring to the internet in a more general sense, you don't need to capitalize it:
* I spent hours on the internet yesterday.
* The internet has revolutionized communication.