From the description of Solid
Users should have the freedom to choose where their data resides and who is allowed to access it by decoupling content from the application itself.
On SAFE users won’t choose where their data is stored, but it’s stored distributed and encrypted on the SAFE network, I’d argue that’s even better. Content stored on SAFE is decoupled from the application and having users store their own data with their own account and choosing who has access, is a natural way of storing user data with an app on SAFE.
Because applications are decoupled from the data they produce, users will be able to avoid vendor lock-in by seamlessly switching the apps and personal data storage servers, without losing any data or social connections.
This would be the most natural way of doing things on SAFE.
Developers will be able to easily innovate by creating new apps or improving current apps, all while reusing existing data that was created by other apps.
In addition to indexes for data, links between data can be created. This could also just be json objects stored on the network, containing relations between objects, such as id1 sameAs id2 if two objects on the network refers to the same entity. Based on these links, indexes could be created to query them, an index could be for example all outgoing relations from an object.
The way I see it, my profile on SAFE should be mine, not any app’s. It will contain my contact list, my files, bookmarks and lots of other things. An app can request to get access to some of this data in the same way mobile apps requests permissions and should work, with some features disabled, if I choose to deny access to some of my data.
I think it is unlikely that solid will ever become more than an academic prototype, but all the problems it tries to solve can be solved with SAFE and it’s a nice project to get inspiration from when making SAFE apps.