We use Google Apps (Gmail) to send and receive all of our email. Our application, which has grown in popularity over the years, sends email to its users per their request. It's not spam, it's important email they ask for.
Gmail (rightfully so) restricts the number of emails you can send. We get around this by queuing our mail and sending it at a slower pace, which works most of the time. We also use multiple email addresses to allow ourselves to send more than the 100-500 email limit.
Is there a way we can send email from our own SMTP server and follow all the proper rules and etiquette to not get flagged as SPAM? This way we can avoid GMail's restrictions.
Are there any good guides for setting up your own email SMTP server to send mail to avoid being flagged as SPAM?
Also, before anyone suggest that I use a 3rd party email sender, I need to be able to send these emails using Java.
(if this question is more appropriate on serverfault, I'm happy to move it)