hey desperado, don't listen to anyone above.
galloper was right that the public will mislead you.
My case was exactly similar to your case.
If your interview took place on 18th July and they did not out-right reject you, then 99% chance is that you'll get the US Visa.
Please don't ask anyone else or read any more comments.
Just act as below:-
On Sunday morning around 9 AM, drop an e-mail to them (E-mail address is [email protected]) stating your bar code number and asking them the outcome of your application.
You'll get the response in Maximum One Hour.
Later you can thank me. :)