http://www.dhs.gov/journal/leadership/2009/09/exciting-changes-at-uscis.html#comment-form
USCIS I-485 Adjudication Manual
****CONFIDENTIAL*********************
1. Guard the backlog information
as a state secret so that I-485
applicants have no idea on how
long they will have to wait;
2. For those have waited really long,
define the term "outside normal
processing time". Only those who
fell "outside normal processing time"
by 6 months can make an inquiry -
BTW, do not feel guilty as nothing is
normal at the USCIS.
3. For those really fell "outside normal
processing time" by 6 months, send a
one-size-fits-all letter indicating
"we are actively processing your case,
please allow us 60 days before
contacting us again."
4. If the applicant makes an inquiry again
after 60 days, send another one-size-
fits-all letter indicating "we are
actively processing your case, please
allow us 6 months before contacting us
again."
5. If the applicant makes an inquiry again
after 6 months, send another one-size-
fits-all letter indicating "we need to
perform additional review and
therefore, the processing of your
case has been delayed indefinitely",
even though the reveiw of the 4-page
Form I-485 takes 10 minutes at the
most.
6. If the applicant makes an inquiry
again, please refer to Step# 5 above.
7. Repeat Step# 6 several times as
necessary.