Periodically I create a virgin Gmail account and sign it up for something, to see what other kind of stuff might end up in the inbox. On February 22, 2010, I clicked on a single "free ipad" co-reg marketing ad, and left the checkboxes checked. I watched the mail coming in for a while, but then forgot about it.
Flash forward to July, 2016. The Gmail account is still receiving marketing mail. Mostly from "Steve" of "Worldstart.com" who apparently doesn't care about mailing addresses that haven't shown any source of life for six plus years. "Steve" is mailing that virgin Gmail address two to four times per day, and has been since April, 2013. Actually, no, it looks like "Steve" was called "Big Daily Sale" before that and has been mailing that address for even longer.
Steve seems to have a dedicated IP address running Lyris software, 188.8.131.52, which has a sender score of 82.
Is it spam? I'm not sure. It might have been one of the original co-reg things I allowed the address to be signed up for, but the brand name changed at some point, and I certainly didn't sign the address up for email from "Steve" directly. And if they're ignoring subscriber engagement, I don't doubt that they're having inbox delivery issues. ("Steve's" mail seems to be going back and forth between the inbox and spam folder in this Gmail account.)
What I can tell you is that I don't think being like "Steve" is the path to inbox success.