The original "web 1.0" was a place to serve static pages built by companies. Along came forums and social media, and we suddenly had a "web 2.0" in which users created and added content. Tim Berners-Lee (inventor of web 1.0) coined the term web 3.0 to mean a web based on data that not only humans, but machines could process. If web 1.0 created an encyclopedia, then web 2.0 was Wikipedia and web 3.0 would make everything on the web into a massive database. How could web 3.0 be securely accomplished and managed? In a word, artificial intelligence (AI).
AI consumes and processes data, and the promise of web 3.0 is to make all of the web into data compatible with AI technologies. That would provide a massive AI training set, most of which is currently inaccessible as "unstructured data." The result could be a step function in AI capability. Imagine a Google, Siri or Alexa search that was able to use all data on the internet: today, if you ask Alexa a question, it might respond with "According to Wikipedia..." and read a web 2.0 article. In the future, it could understand the meaning of everything online and provide a detailed answer.