When you sign up for Tracker an account and Tracker login will be created for you by default, using the information you provided. For more on the differences between accounts and logins, please see Understanding accounts and logins.
We are no longer allowing the creation of new accounts. However, if this creates any issues for you during the remainder of Tracker’s time, please contact us at support@pivotaltracker.com and let us know more about your needs. Thank you for your understanding.