No, giving my e-mail address is just that - giving an email address; it does not come with permission to send automated daily emails. For example, I login to facebook with my email address, but I have explicitly withdrawn any permission for facebook to send me any notifications by email in all the opt-out settings.

Subscribing to messages should be explicitly opt-in, and in a bunch of countries is legally required to be opt-in. If I miss an opt-out checkbox, and you send a marketing email - that is spam by definition, if gmail decides to filter you out, then by all means it was the right thing to do; and if it was a local business, they would be fined for that.

Luckily, the customer still has control over what spam means to them. If you're requiring an e-mail login on your site just so you can loophole your way into inundating me with e-mails sent by a machine, then I'm marking it as spam.

Whether or not we consider that "spam" is a semantic argument. I do, because it litters my inbox and pisses me off. I recognize that people may want to distinguish it from bulk email from entities that you have no prior relationship with, but to me, that's immaterial.

I don't know why you are quoting spamhaus definition for spam, that is not relevant for the GP. Neither is the can-spam acts definition.

I use (and suspect the GP does too) use something like the following definition:Spam is email you don't want - it doesn't matter if you signed up with a company or not if you don't want a particular email it is spam.

Now as a practical matter I tend to click unsubscribe if it exists, mostly because otherwise the spam filters quality drops too far, but I still consider it spam.