This picture above shows a simple abstraction of web evolution.
The traditional World Wide Web, also known as Web 1.0, is a Read-or-Write Web. In particular, authors of web pages write down what they want to share and then publish it online. Web readers can watch these web pages and subjectively comprehend the meanings. Unless writers willingly release their contact information in their authored web pages, the link between writers and readers is generally disconnected on Web 1.0. By leaving public contact information, however, writers have to disclose their private identities (such as emails, phone numbers, or mailing addresses). In short, Web 1.0 connects people to a public, shared environment --- World Wide Web. But Web 1.0 essential does not facilitate direct communication between web readers and writers.
The second stage of web evolution is Web 2.0. Though its definition is still vague, Web 2.0 is a Read/Write Web. At Web 2.0, not only writers but also readers can both read and write to a same web space. This advance allows establishing friendly social communication among web users without obligated disclosure of private identities. Hence it significantly increases the participating interest of web users. Normal web readers (not necessarily being a standard web author simultaneously) then have a handy way of telling their viewpoints without the need of disclosing who they are. The link between web readers and writers becomes generally connected, though many of the specific connections are still anonymous. Whether there is default direction communication between web readers and writers is a fundamental distinction between Web 1.0 and Web 2.0. In short, Web 2.0 not only connects individual users to the Web, but also connects these individual uses together. It fixes the previous disconnection between web readers and writers.
We don't know precisely what the very next stage of web evolution is at this moment. However, many of us believe that semantic web must be one of the future stages. Following the last two paradigms, an ideal semantic web is a Read/Write/Request Web. The fundamental change is still at web space. A web space will be no longer a simple web page as on Web 1.0. Neither will a web space still be a Web-2.0-style blog/wiki that facilitates only human communications. Every ideal semantic web space will become a little thinking space. It contains owner-approved machine-processable semantics. Based on these semantics, an ideal semantic web space can actively and proactively execute owner-specified requests by themselves and communicate with other semantic web spaces. By this augmentation, a semantic web space simultaneously is also a living machine agent. We had a name for this type of semantic web spaces as Active Semantic Space (ASpaces). (An introductory scientific article about ASpaces can be found at here for advanced readers.) In short, Semantic Web, when it is realized, will connect virtual representatives of real people who use the World Wide Web. It thus will significantly facilitate the exploration of web resources.
A practical semantic web requires every web user to have a web space by himself. Though it looks abnormal at first glimpse, this requirement is indeed fundamental. It is impossible to imagine that humans still need to perform every request by themselves on a semantic web. If there are no machine agents help humans process the machine-processable data on a semantic web, why should we build this type of semantic web from the beginning? Every semantic web space is a little agent. So every semantic web user must have a web space. The emergence of Semantic Web will eventually eliminates the distinction between readers and writers on the Web. Every human web user must simultaneously be a reader, a writer, and a requester; or maybe we should rename them to be web participators.
In summary, Web 1.0 connects real people to the World Wide Web. Web 2.0 connects real people who use the World Wide Web. The future semantic web, however, will connect virtual representatives of real people who use the World Wide Web. This is a simple story of web evolution.