Iris username helps users to find your nostr profile easier outside of nostr. It's easy to share.
The format is iris. to/ username (for example: iris.to/sirius).
You can also use [email protected] format (NIP05; e.g. [email protected]) in user searches. NIP05 is a unique identifier but it's harder to explain to people unfamiliar to nostr.
#nip05 #username #search