It’s not “an app”, it’s a protocol on which a bunch of apps are being built which means a ton of different use cases can arise all serving the same userbase (anyone with an npub).

So you might arrive via the Twitter clone Damus, then go to the Reddit clone https://nostr.kiwi, then the Substack clone https://habla.news, then the Clubhouse clone https://nostrnests.com

Then comes the Insta clone, then the OnlyFans clone, the TikTok clone etc etc etc etc

Nostr will scale much differently to any of the platforms you are used to and will come in different bursts - Users leaving Big Tech platforms, local use cases such as Conferences or CivKit, protests, etc.

Wouldn’t want to be anywhere else right now, #nostr has the best chance to succeed of anything new since Bitcoin