When it comes to send a bulk email like a newsletter or a commercial offer to a large number of addresses, it’s crucial to understand that only a professional SMTP server can do the job correctly.
In fact, any common outgoing mail server like the ones you find associated to free providers (Yahoo!, Gmail etc.) isn’t structured to manage such a wide mailing. First of all because there are some limitations about the number of addresses you can handle for each single sending; and secondly, because your bulk email will be probably get filtered out by the majority of incoming servers. You will, in a word, be considered as a spammer even if you’re doing permission-based email marketing.
Awful, isn’t it?
So to guarantee that your mass email will be correctly delivered to all recipients, you must rely on an SMTP server which has been aptly designed to support bulk mailing: which keeps a constant dialogue with all major ISPs and works hard to avoid any kind of dangerous blacklisting. It’s the only way to make the most of your newsletter and do some really professional email marketing.