Decentralized as in not needing a central server.

I don't know about Loops specifically, but generally [Fediverse][0] projects tend to:

- Not rely on a central server.

- Allow you to set up your own server.

- Connect to a web of other servers through the Activity Pub protocol.

- Allow you to modify policies on your server (including restricting which other servers information is shared with.)

Many are also open source.

The creator of Loops also built a different project called [Pixelfed](1) with a focus on decentralized photo sharing (although it can also host video.) Because all these projects speak the same protocol, it's possible that at some point, Loops could show content from Pixelfed. Apparently Loops content is already appearing in Mastodon.

Meta's Threads also has Activity Pub support. Hypothetically, Threads content could appear on Loops and vice versa, if the UI is built to accommodate that style of content and a server admin doesn't block the Threads server (many servers block Threads specifically.)

TL;DR: A web of servers using different pieces of open source software to share social media, without a centralized server.

- [0] https://fediverse.info/

- [1] https://pixelfed.org/

Just a side note, reading through some of the other comments, it sounds like Loops specifically isn't currently open source and the intent is to open source it at some later date.