How do spammers know an email is active?

Question

I recently put my old Hotmail account on my phone, which I traditionally only checked a few times a year. I went from 1-2 spam emails every few months to several a day, after going through all the old ones and marking them as spam. How is this possible? I haven’t given this email out in years, and none of my monitoring services have flagged this email recently. It seems spammers somehow know this email is active again.

In: 146

Answer 1

> I recently put my old Hotmail account on my phone

Potentially you have an app on your phone that is collecting your contacts and account information and selling it to marketers