From his Medium post "In 2009, I said, “The web as I envisaged it we have not seen yet.” That was because people were using the web just for documents, not for the data of a big web-wide computer. Since then, we have seen a wave of open data, but not of read-write data. For example, much open government data is produced through a one-way pipeline, so we can only view it. With Solid, it becomes a read-write web where users can interact and innovate, collaborate and share."
https://medium.com/@timberners_lee/one-small-step-for-the-we...