I love getting early access ... so I decided to test your product a bit and it was completely unexpected for me that the username "
@username" was available for registration, and I took it ..
(although for example usernames such as "Bitcoin, Crypto, OgAss" were already taken). As for the product, I like the idea and the interface, but I'll write about that a little later.

Thank you for your comment and support!
Meanwhile, it is not suggested to use common name/word like "Bitcoin" and/or "Crypto" to be username, since it may confuse the receiver of sender's identity.
We will continue to improve the service and, hope it can benefit more people.