Solid uses a [Internationalised Resource Identifier (IRI)](https://tools.ietf.org/html/rfc3987) as a WebID, requires an IdentityProvider; can be multiple Identity Providers.
The rights on a Pod are attached to WebIDs. WebIDs may refer to a person, a family or an organization. Instead of creating an account on each app, the app finds your WebID.
Pod is a data storage space. All a user's data is stored here. Applications read and write data into the Pod depending on the authorisations granted by the user or users associated to that Pod. A person may have multiple pods, for example for work and for home. Data may be replicated across pods.
Users may self-host their pods (on their own server) or use a "Pod Provider".
Users may also switch pods easily without losing their data (such as their contacts and chat history.
WebID allows user addressing across all Solid-conforming apps
There does not seem to be a Solid-based social network as of this writing, some discussion about creating one. Instead, Solid aims to create tools that enable building of decentralized social applications.
The owner of the pod controls access to who is authorized to read or write data. However if the user revokes access of an app to their data, the app can't further read or update the user's data, but they would still have the data that the user sent out prior to the revocation.
Data is always encrypted when in transition between an app and your pod. Note that pod providers don't necessarily have to encrypt the data on your pod.
Pod providers may or may not charge for hosting a pod. This will be determined by the market. They are hoping several business models emerge, some where the user pays for storage, and some funded by advertising for instance, like on the current Web platforms. Not clear which models are currently in use.
### User experience (if applies)
The Solid ecosystem includes apps built to use solid data pods.
Example apps:
[dokieli](https://dokie.li/) for publishing articles/posts
[exhaustive list of apps built on Solid](https://solidproject.org/use-solid/apps)
Solid doesn't have its own sense of messages per se, but a Solid pod could be used for example in the implementation of an ActivityPub server.
The minimum requirement to be 'doing Solid' appears to be the use of JSON-LD (linked data) - discussion of [a subset of JSON-LD](https://stephank.nl/p/2018-10-20-a-proposal-for-standardising-a-subset-of-json-ld.html)
Some work on ActivityPub that is
[discussion of links between ActivityPub and Solid](https://socialhub.activitypub.rocks/t/which-links-between-activitypub-and-solid-project/529/8)
Published paper [Solid: A Platform for Decentralized Social
Applications Based on Linked Data](https://pdfs.semanticscholar.org/5ac9/3548fd0628f7ff8ff65b5878d04c79c513c4.pdf) indicated sub-linear scaling with number of users/pods.
