Hi there.
On the lists "wikimedia-sk" and "wikimedia-sk-oznamy",
where I am admin, we have received suspicious mass
subscriptions (several tens in several hours). They came from
nowhere, all with @
aol.com address (very unusual for
our target group) and all declared only first name. Most
certainly some bot.
Provisionally I have set them all for moderation.
Eventually I could block subscriptions from @
aol.com
addresses (no too big deal, because hardly someone real in our
audience is using them) but I prefer systemic solutions and
not to cure symptoms. And possibly someone else here is
running into the same problem.