Database of numbers and e-mail?

Question

Fight against spam

Question.
From where mailers and spammers get databases of mobile phone numbers. What are the ways?
And also where do the e-mail databases come from?

Answer 1

Phone numbers are easily bought at any communication office, they usually turn to large centers, because. there are the most registered
ones. As for email, there are several options:
1) When registering on a site, this information is also merged for shishi
2) Write an email and get a book, coupon, etc. further according to the first scheme
3) Poke at random