So it has come to my attention that at least some countries use automated mail sorters that are capable of deciphering human written addresses. More importantly, some countries are starting to store databases of all mail routing information. I was told this by a very trusted source, although I am digging around for technical specs of mail sorters right now (love open source intelligence!). This is scary. Let's say Alice buys a pack from Bob. Bob is known to ship from netherlands. Alice gets the pack with no interception. WOOT. Then Alice leaves feedback on Bob saying that she got her package. Next Alice orders from Carol. Carol ships from New York. Alice gets her package with no interception, and then leaves feedback on Carol. The DEA is not happy. They want Alice to fuck off. So they query mail sorting records and look for everyone who got a package from Netherlands in X time frame around when Alice left a review for Bob, in addition to everyone who got a package from New York around the time frame that Alice left a review on Carol. Lots of people are probably in both of these crowds. Now they intersect these two crowds, and out pops Alices shipping address. My source tells me that he is absolutely certain and knows for a fact that some nations have sorters that log this information. He is not sure about other countries. edit: The person who told me this says it is unlikely that police agencies can (legally) gain access to this information, but that intelligence agencies certainly have access to it. https://en.wikipedia.org/wiki/Optical_character_reader http://www.toshiba.co.jp/sis/en/scd/postal/lsm.htm edit II: hmm maybe police can legally gain access to this information.... https://ssd.eff.org/book/export/html/16 www.cryptome.org/isp-spy/usps-spy.pdf USPS mail cover procedure edit III: In some countries only intelligence agencies can legally access mail routing information without a specific warrant (law enforcement can check routing information of certain people with a warrant, but they can not do blanket analysis of stored routing information), USA is *not* one of those countries (USA citizens have a right to privacy of mail contents, but not routing information....there is no law preventing police agencies from doing the attack mentioned in this post.) edit V: Apparently it is against USPI procedures to use mail covers as an initial investigatory technique. I am not yet sure if this is protected by law or not, but from the EFF information it appears not to be.