1) e@gle eye - profiling by people at the counter
2) IRS/USPS mailing DB. Where did you think the data you put on forwarding cards really went?
3) To/From "metadata" DB. One of the "s*curity enhancements" that went in with the 3 cent postage increase in the wake of 9 I1 was the metadata database that tracks every to/from address combination that goes through the mail. It wouldn't suprise me if they now also had access to
3a) every to/from address combination that fedex and ups has
If you haven't noticed beginning 2013 there's 4). 4) for anything larger than normal first class mail there's a tracking number sticker now put on every piece. And, something that I can't verify but suspect from how my mail has looked in the past years.....
They're down now to flat out opening mail and resealing it in their s*cur1ty centers.
Also, have you noticed you can't buy strapping tape anymore? Just clear RESEALABLE mailing tape? hmm...