title: SMTP servers for bulk mailing
body: <p>I got the authority from the user, and they subscribe to my newsletter.</p>
  
  <p>Are there any free bulk mailing SMTP servers?</p>
  
  <p>If not, which service (e.g., MailChimp) offers the largest mail-sent limit and subscriber limit?</p>
  
  <p>In fact, can I build my own SMTP server and serve email just like MailChimp, given that my computer can handle the workload? </p>