As an immigration attorney I sometimes have consultations with people who are in removal proceedings because they did not receive a notice from USCIS (at least that’s what they claim). Other times people view their case status online and see that their case has been approved yet weeks or months have passed and they still have not received their green card, travel document, employment card, etc. in the mail. They would call USCIS for more information and all USCIS could tell them is the date that the document was mailed. USCIS was unable to confirm the delivery of the document.
USCIS has come up with what I think will be a good solution to this problem. In early May 2011 USCIS announced that it has fully implemented the Secure Mail Initiative (SMI). SMI uses the United States Postal Service’s Priority Mail with Delivery Confirmation to send documents. SMI also provides USCIS “customers” with tracking numbers so that they can track the delivery of their documents. The other upside to using priority mail is that delivery is several days quicker than it is with first-class mail, USCIS’s preferred method of delivery in the past.