#Alexandria also reads and writes to the user's relays (from their npub profile's relay list), and our relays broadcast/pull from lots of other relays, on the backend. The events can be published to any almost any relay.
If you don't login, our default relays are used, such as wss://theforest.nostr1.com.
We archive old things (including things we've downloaded from other archives), but you can also write something new and publish it as Nostr notes.