Distributed Ledger Technology (DLT) can either be permissioned or permissionless. This is the foundation of blockchain. Most that are set up, like Bitcoin and Ethereum, are permissionless meaning that anyone can write to them. They are public in reading also.
At their core, blockchains are ledgers. They track the transfer of value through coins and tokens. Effectively, they are a medium of exchange outside the traditional monetary system which is controlled by the banks. In the present financial system, this is who runs the ledgers.
A permissionless blockchain allow anyone can write on-chain. This means they are adding data to the distributed database. As long as they have the private key that is attached to a particular wallet, that is the only thing required. To base layer code handles the rest.
Permissioned Chains
There were some chains set up, primarily by the banks, which were permissioned. Around the middle of the 2010s, IBM was trying to sell companies on the idea of permissioned blockhains. Essentially, these are databases run by a number of companies that have permission to update the records. The problem that IBM ran into is that distributed ledger technology was around since the 1990s. Satoshi Nakamoto changed the landscape by bringing decentralization to DLT, making it permissionless (he also solved the double spend problem).
Most permissionless blockchain have some type of transaction fee required for writing to the ledger. This aligns with finance since most transactions in that realm incur a fee. It does, however, not go over well with social media. Who wants to pay to give a vote or even a comment?
Social Media
This is the challenge for Web 3.0? Most websites or platforms under Web 2.0 are permissioned. Applications like Twitter or Facebook provide "free" use of their servers, allowing anyone with an account to write on the network. This does require their approval, something that many found was often removed. There is also a question of how free it is since those entities often sell people's data.
A couple were able to solve this problem.
Steem is a social media blockchain established in 2016. It was founded primarily around blogging. It was able to reward content creators for their articles they posted. This was done without a transaction fee.
This was further enhanced by the fork that created Hive. Here is an ecosystem that is fast and feeless while also having censorship resistance. The decentralization of the node system means nobody can shut down an account or change the data posted in blocks. All data is on-chain where anyone can see it.
It is a system that has a non-tradeable token that is the result of staking the main coin. The resource credit system established the "permission" required. As long as an account has the necessary RC to perform an activity at the base layer, it cannot be stopped.
This allows for social media engagement in a permissionless, feeless manner.