They have been doing mail that way for years... even before 911.
You wont notice on the letters you receive but each one of them has an invisible barcode placed on it by the post office.
Pretty fascinating stuff..... The post office wants you to address your mail clearly using block letters not to make it easier for the mail folks to read but so that the optical scanners can read it.
They probably do store the images now with 911 and all...... but the process of optically scanning the mail is not sinister in any way...it just makes mail sorting more efficient.
YOU SHALL REAP WHAT YOU HAVE _______ SOWN