Solid is a platform, built using the existing web. It gives every user a choice about where data is stored, which specific people and groups can access select elements, and which apps you use. It allows you, your family and colleagues, to link and share data with anyone. It allows people to look at the same data with different apps at the same time. Solid unleashes incredible opportunities for creativity, problem-solving and commerce. It will empower individuals, developers and businesses with entirely new ways to conceive, build and find innovative, trusted and beneficial applications and services. I see multiple market possibilities, including Solid apps and Solid data storage.

https://medium.com/@timberners_lee/one-small-step-for-the-web-87f92217d085