Sending an email to about 10K users (NOT SPAM!)

Solution 1:

If you have a website that has that many users, I guess you have full control over a server.

I highly recommend you install PHPlist. It is overkill on small sites, but for a site with as many users as yours, it has many nice features such as auto pruning of dead addresses (and on a 10k list, you need it!).

Full features

Solution 2:

Preventing your server from being listed on one of the many spam blacklists (you can check if you are already listed here) and managing/configuring the underlying mail server (postfix etc) is a considerable amount of hassle. If you are considering sending more than one mail to your subscribers, I would recommend outsourcing this to a 3rd party such as mailchimp (pay as you go pricing would be preferable). There is also a free version for up to 500 subscribers.

If you simply require a single mail shot, then make sure:

• Your server has MX and reverse DNS records
• You have SPF DNS records (many servers reject mail without a valid SPF, GMail for example)
• Your mailserver's HELO response matches your hostname
• Your mailserver is not an open relay