[RyJones]

perhaps it's a parsing error, like the bug yesterday about usernames may not end in MIME types? SMSC[0] is re-implemented many times.

0: https://en.wikipedia.org/wiki/Short_Message_service_center

[duskwuff]

Given the context, it's absolutely a spam thing. When the .XYZ gTLD launched, registrars were incentivized to discount it aggressively, sometimes as low as $1 for the first year. Spammers loved this.