Since the Internet started here in the United States, we had the advantage that the initial websites and domain names were based in English, so that is why we see most of the content of the web in English, although that has started to change, but it will take a while that English as the predominant language of the Internet will be challenged. You do find most of the stuff in English and even if you can’t some of the popular websites in other languages have translation software to translate the foreign languages into English.
Moreover English although not being a native language of the majority of the people of the world is the most widely spoken due to the fact that China and India, the most populous countries of the world, communicate in English language or have it as a second language. A recent article had described that the English language will decline since the native population is not growing but guess what the article was written on an English website. In order to understand each other, most of the world communicates in English and I don’t see any major challenge to its supremacy any time soon.