Jack Dorsey is the founder of Twitter, who also led Twitter as CEO before. After leaving Twitter, he focused on financial services Square, and now also develops his own social application, called Bluesky.
Bluesky focuses on offering more or less the same as Twitter, but includes decentralized technology elements to it.
Bluesky offers an experience more or less the same as on Twitter, including being able to follow the desired account, in addition to sending shares, or replying to someone's shares.
This application is equipped with the AT protocol, which is a technology developed by Bluesky itself. It also makes it easier for you to communicate with anyone who uses the service under the AT protocol, as well as allowing you to change hosts without losing identity or content.
The AT protocol also gives freedom to users in choosing an algorithm openly and is not subject to a service provider itself.
For now, Bluesky is still in closed beta, and requires an invite before you can use it. It is not yet known when this Twitter competitor will be officially introduced to everyone publicly.