When you sign up for a Yahoo!7 account, you're assigned a Yahoo!7 ID. This is a permanent, unique identifier for your account. There is no connection between a Yahoo!7 ID (the bit before the @ in the Yahoo!7 email address), and a Yahoo!7 Video nickname.

Your Yahoo!7 Video nickname could be the same as your Yahoo!7 ID, or it could be different.

Read more about Yahoo!7 Identities and Nicknames