I\'m working on an application that will allow management to send registered users (opt-in) broadcast emails at regular intervals, or based on various other criteria. In any ca
Yes, I've had spam list problem with mailing lists of that size, managing email lists for non-profits.
One wants to take extra precautions: make sure your email has SPF records, write a script to send the emails in batches, paced out over time. Definitely send them one one at a time, not as bcc, as direct mail has a better chance of arriving. Make it very easy to unsubscribe. Include people's subscribed email in the message sent -- often people have email forwarded to another account and then try to unsubscribe that account and get frustrated.
Even so, don't be surprised if you have to change your IP at some point.