I'm the sysadmin for the United States Geological Survey's Earthquake Notification Service. This is a free service provided by the U.S. Department of the Interior where people can sign up for automated notifications of worldwide earthquakes. The subscription process is opt-in with confirmation of addresses, so there's no way for someone to subscribe another person's address without their knowledge and cooperation.
We have almost 350,000 subscribers, and a fair number of them are Verizon customers who signed up to get short-format alerts sent to their phones via the email-to-SMS gateway at vtext.com. They subscribe by putting in their email address in the form 1234567890@vtext.com. We've been doing this for about five years now.
Starting about two weeks ago, I started getting hundreds and hundreds of failure messages back from postmaster@vtext.com. They all say the same thing:
Error: Invalid user address
Error message below:
550 - Requested action not taken: no such user here
Message details:
Sent date: Fri Jun 08 22:27:51 GMT 2012
MAIL FROM: ens@usgs.gov
RCPT TO: XXXXXXXXXX@vtext.com
From: ens@usgs.gov (USGS ENS)
To: XXXXXXXXXX@vtext.com
Size (in bytes): 144
Number of lines: 1
Anybody know what's going on here?