Yes it is. It is malware at this point. (It’s trying to trick you into clicking ads.) If I can invite you to try Port87, it’s an email service that I wrote that does the opposite. (Keeps spam out of your inbox, rather than inserting spam into it.)
Full disclosure: I developed and run Port87, and as such, have a financial interest in it.
Isn't that labels thing the same as using the + in Gmail? You can use myname+spam@gmail.com to register somewhere, and if you receive anything else on that email address you'll know they shared your email address.
Kind of. It’s called tagged addressing or subaddressing, and the fact that you can do that with both services is where the similarities end. With Gmail, it’s just another address that goes to your inbox. With Port87, whatever you put after the dash or plus sign is the label it goes to in your account. That way, it’s automatically organized for you. And you can make a label screen senders before their email is delivered. That way, a label that’s meant for people, like “yourname-friends@port87.com” will only get emails from real people.