Spam is unsolicited bulk email. Since too many services ask for an email address, and do not ask permission to email you anywhere in the sign up, many services are on the spammy end of just about acceptable. Really, it's a misuse of the "Emailing someone who has a business relationship to you is fine" clause. People creating an account out of curiosity do not have a business relationship and are not really giving you permission to email them.

People need to understand this because receivers will happily misuse spam reporting tools. Even when following best current practice some email will end up flagged as spam, but this can be improved by following bcp.

Just for extra clarity because I mangle this stuff sometimes.

> Spam is sending someone email when they've never contacted you before

That's why the email address needs to be confirmed; to prevent someone using another person's email address. That doesn't need to be malicious. There are examples of people mistyping domain names and having all their email sent somewhere else.

> or still sending someone messages when they've asked you to stop.

Really people need to include a checkbox, that defaults to [NO], asking for permission to send email when the account is created. Just being given an email address isn't enough, especially if one is needed to see anything about the product.