If they default to opt-in, instead of default to opt-out, then it's spam.
For example, it's reasonable for an account manager to email you as a customer and see how the product demo is going and ask if you need any help with something. If you don't care to hear from them, then let them know but that is not spam.
Spam is sending someone email when they've never contacted you before or still sending someone messages when they've asked you to stop.
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.
Spam is someone contacting you to market a product when they have never had contact with you otherwise.
Remember that "Do Not Track" header? I kind of wish that had gone forward, but slightly differently--with something more like a "Don't Try To Interact With Me; Pretend I'm Not Here" header.
You know how, in most brick-and-mortar shops, it's a sales rep's obligation to make sure that every customer in the store has been asked "if they need anything" at least once? And how for a certain subset of the population, you often wish you could come into the store with a big flashing neon banner above your head saying "I'M JUST BROWSING THANKS" so they'd know in advance not to do it? ...except that, obviously, that would be horrible?
On the internet, it wouldn't have to be horrible at all.
ABC simple.
Confirm the address, and make sure you have permission[1] to send to that address, before sending to an address otherwise your email is exactly the same as 419 scam and goji berry email.
[1] Either from a checkbox where the user has opted in or a pre-existing business relationship. And that's not "I gave you my email address to download your app".
It's not spam. Don't sign up for the site if you don't want to get emails from them. Or, be courteous and use their unsubscribe link.
You signed up for their site to get their service/product/whatever, and their terms state someplace that you'll get emails from them. That's part of doing business with them.
Let me repeat, just to be clear.
"IT'S NOT SPAM".
Unless, of course, you're one of those whose definition of spam is "any email I don't want".