The address will get registered at 300 different online newsletters. Almost all newsletters (95%+) will send a letter to welcome the 'new customer'; 50% of them will request a confirmation of the address. This isn't that bad, the address still will be registered at 50% (~1500) newsletters without confirming the address and will receive some spammy mails every day/week/month. So in total, the address receives 3000 messages in the beginning and several hundreds of messages every day.
But do the mails go in the inbox or spam?
The subscription list contains only serious websites like Amazon, Pinterest, The New York Times, etc. Because mail servers won't detect anything and will let all mails go through to the address inbox. Only 1-10% of the mails are marked as spam, the rest goes directly into the inbox!
Disclaimer: Use only with email addresses that are yours.
Bomb any email!
I will bomb any email in under 2 days!