I make one-off email addresses for nearly every online vendor I deal with. Usually, the addresses are in the form of domainname@peeved.org, as is a common practice with people who own domains.
My one-off address for tickets.com started receiving spam on 5/11, from the Unitarian Universalist Society of Cleveland by way of a spamming service at Constant Contact.
Sure, sure, I could "unsubscribe". Since I'm not going to do any more business with Tickets.com, I'm just going to blackhole the email address anyway, but it does make me wonder how these Constant Contact or UUSC people got the address to start with.
Here are the two messages I received: Message 1 and Message 2.