Defining spam

This is a post I’ve put off for a while as the definition of spam is a sticky subject. There are online fora where the definition of spam has been debated for more than 10 years, and if there isn’t a working definition after all that time, it’s unlikely there will ever be a definition the participants can agree on.
This came up again recently because one of the comments on my “Reputation is not permission” post took me to task for daring to call the mail “spam.” I’m going to assert here that the mail was unsolicited bulk email. I did not ask for it and I know at least 4 other people that received it.
The commenter, and a few marketers, argue that if the mail is sent without any forgery and the mail contains an opt-out link then it is not spam. It is a definition I have only seen folks who want to send unsolicited bulk email use, however. What they are really arguing is their mail isn’t spam because they provide a valid return address and a way to opt-out. Few people actually agree with this definition.
Here are 10 of the many definitions of spam that I’ve seen.

1. Unsolicited bulk email.
2. Mail that violates CAN SPAM.
3. Mail that the recipient doesn’t want want.
4. Unsolicited bulk commercial e-mails to an individual’s e-mail address without having an existing or prior business/personal relationship or obtaining consent/permission.
5. Any commercial email.
6. Any mail that is bulk and that lies about either the identity of the sender, the offer or the ability to opt yourself out.
7. That which I do not do.
8. Irrelevant or inappropriate messages sent on the Internet to a large number of newsgroups or users.
9. Unsolicited e-mail, often of a commercial nature, sent indiscriminately to multiple mailing lists, individuals, or newsgroups; junk e-mail.
10. Unwanted or unsolicited commercial e-mail message from someone you do not know or with whom you do not have an established business relationship.

So what is your definition of spam? (and am I absolutely nuts for asking the question?)