#HOWDONOSTR
What is a Nostr address?
It's a human readable identifier for your public key. It makes finding your profile on Nostr easier. It makes identifying your Nostr profile easier. A Nostr address is much easier to remember than a long and confusing Nostr public key. A Nostr address, also referred to as a NIP-05 ID, additionally provides you with a shiny verified checkmark on many Nostr clients.
Please be aware though, that this is not the same type of verification that you'll find on centralized platforms. The only item that's being verified here is that an npub on Nostr corresponds to a particular username and domain. The checkmark shows that a Nostr address is valid and that's it.
This checkmark helps put a stop to spammers and scammers on clients that showcase valid and invalid Nostr addresses. For example, if you're looking to follow Derek Ross on Nostr, you'll see many different Derek Ross profiles exist. If you're not sure which one is correct, you should look for the profile that has a valid checkmark besides the Nostr address derekross@nostrplebs.com.
For certain well known individuals or well known companies with their own popular or well known website, it makes sense for them to use the website or organization that they're representing for their Nostr address. For example, maybe a Nostr user works at Tidal. They would use user@tidal.com. This shows that the user works for or is employed by the popular music service Tidal.
For other users that don't have the technical knowledge or the time to set up their own personal Nostr address, they may choose to use a Nostr address service provider. The first and most popular Nostr address service provider is NostrPlebs.com. Many other service providers now exist and offer similar services.
For more information, visit the Nostr NIP-05 official documentation.