Had to create an account to simply see what it's all about - it isn't for me. How do I request cancellation/deletion of my account, userid, password, etc.

You can't delete your account, but you can clear it using the Clear and Start Over function.  To do so, while logged into your return:

• On the left hand side of your screen, click on "Tax Tools"
• From the drop down menu, click on "Clear & Start Over"
• You will be asked whether or not you want to clear your return.  Clicking yes will erase your information.