Depends. You're not going to be able to follow celebrations, organizations, or your IRL friends (unless you badger them about making an account). Might change if Nostr grows, or if Activity Pub grows (Nostr is bridged in to the fediverse).
Still a cool place to talk tech and other random topics, or experiment around with the tech. I've also found it to be full of nice people with less chaos than Twitter.
All really depends on what you're looking to get out of it.
Nope, not interested in following kinds of things you've said.
Sounds cool...So it looks like Reddit ? but not centralized, is it ? And where are our msgs stored, in the "relays" ? or distributed among client phone / desktop / etc ?
I'm not sure I understand your questions.
Nostr is, indeed, decentralized (not centralized). Unlike, for example, Mastodon, it's decentralized in a way that provides censorship resistance and doesn't tie your identity to a specific server. Your messages are, indeed, stored on relays. "Relay" simply means "server" in the context of Nostr: it's just the name they have. Clients can also locally store messages, but they do not have to and it's not how the protocol works.
Regardless of the level of your technical skills, I encourage you to look up how Nostr works and even read NIP-01. It really isn't complicated and you don't need much of a background in CS to understand it. Chances are, if you know well enough to be using Nostr and to ask those questions, which you do, you'll be able to understand NIP-01, which is the core and the required part of the Nostr protocol.
But do ask if you have any question.
NIP-01: https://github.com/nostr-protocol/nips/blob/master/01.md
Nothing wrong with that. You can probably find content of all stripes, but since the platform's new and it's main draw is it's technical capabilities, most of us are somewhere on the "interested in tech" van diagram so that could probably get annoying if you're not interested in it.
It's not exactly like Reddit, it's definitely more of a decentralized Twitter (though there are experimental Reddit style communities being built on Nostr as well - though most clients don't support them atm). Like Valentino said, messages are stored on relays. The thousand foot view is a message is signed by your client using your keypair, uploaded to all of the relays you set your client to use, and then other clients can download your messages from those relays.
