The CommerceV3 software has been updated to allow you to decide whether or not to send an email confirmation to a new member after sign-up. Settings> Options> Member Options>Would you like to send customer an e-mail confirmation after registering as a member
By selecting Yes an email will be sent to the new member.
By selecting No an email will not be sent.
If you would like to review or make changes to the Member Registration Email you can go to: Design> Template Library> Email Confirmation Templates> Member Registration Email (member register email.tpl).