A couple of days ago, a couple of the list admins on fedora lists were noticing an uptick in subscription attempts for an address @mms.att.com which is basically an email to MMS gateway. The reason they were seeing this was because the ATT was blocking and sending back a helpful email saying "This person does not accept unsolicited text emails." Doing some investigation it turns out that this person was actually one of 20 or so people who were getting attempts to auto-subscribe them to every Fedora list. For people at gmail.com and other email addresses they used the "filtering" technique of
Doing a simple google search of a couple of the emails and looking at some of the posts related to them in Facebook and Twitter, the only common thread was that they had all gotten involved in messy breakups. So my weak conjecture is that someone has created a "Revenge Spam" site where you pay them, give them an email address and they sign that email address to every mailing list etc to make their lives miserable. This type of things isn't much different from the old "sign up my ex to Columbia House Tapes/Records/CD collection" and every magazine with a free insert for N magazines before being billed. It is a pain and petty.
In any case, if you run into this and are using mailman2, you can add filtering per list using the amazing Mark Shapiro's ban module which will allow for various regexp so that when they change from
[Thanks to Kevin Fenzi for finding this link http://firstname.lastname@example.org/msg67312.html as google and I were having a disagreement on what I meant by filtering and this showed up on page 4 of my google search and page 1 of his.]
In any case, you should check the /var/log/mailman/subscribe for a large growth in subscription attempts of the same email address from multiple ips. I am going to see what we need to do to block this on the mailman3 side of things and will hopefully post a followup with that info.
[To the people who got a ton of email requests to subscribe to N mailing lists.. I apologize for not catching this earlier.]