Everything you’ve ever done on Facebook that sent a notification to someone — Facebook sent your computer’s IP address to them in the header of the notification e-mail.

I just tested it on some old notification e-mails and sure enough, it’s real.

It doesn’t always work — sometimes I got the “home” IP (127.0.0.1), but that their software is even designed to do this is alarming.

The worst part is the name of their mailer program. Zuckmail? Are you serious?

http://jwz.livejournal.com/1234802.html

UPDATE:

I did, in face, go through a dozen or so old e-mails. I am disturbed to have discovered how accurate this is.

IP, Base64 encoded, in every notification e-mail, tagging the initiator of the notice by their IP address. On the left are the IPs. On the right is the ARIN info.

Old friend from college who works for a lobbying firm in Sacramento.

192.234.214.x, Office of Legislative Counsel – Legislative Data Center

Friend with an iPhone, back when she had a BlackBerry on Verizon Wireless.

75.215.14.x, Cellco Partnership DBA Verizon Wireless

Friend at UCSD. Not sure why he was in Atlanta that day.

68.101.173.x, Cox Communications Inc.

Friend with an iPhone.

12.130.119.x, AT&T Wireless

Friend who used a shady Facebook app to tag me in a photo. App was hosted at Slicehost, interestingly.

173.203.210.x, Slicehost

Friend who works on the Paramount lot.

204.110.112.x, Paramount Pictures

IANA comes up a couple times. Not sure why yet.

10.22.110.x, Internet Assigned Numbers Authority

Got nukes? Friend who is working on her PhD at RAND.

130.154.0.x,The RAND Corporation

Now I know this friend has a cable modem and TimeWarner as her ISP.

98.148.210.x, Road Runner

This friend is has a DSL on ATT.

76.194.238.x, AT&T Internet Services.