At present, iMail cannot be sent to regular email accounts. iMail addresses are called iMail destinations. They are much longer than the average email addresses and do not carry the "@" sign nor a domain. They already include the encryption key, so using an iMail destination is not harder than using standard email with gpg encryption. The destination is two in one: the "address" as well as the public key. In contrast to gpg- or pgp-encrypted emails, I2P-Bote also encrypts the mail headers.
