Using email class for large distributions

[eluser]Derek Allard[/eluser]
For lists that large, you may want to seriously consider a third party sender like constantcontact or mailchimp or campaignmonitor (I'm not affiliated with any of these services). I'm not saying CI can't do it, just that there is so much other stuff to consider (spam blocking, false blacklist reports, etc) that it probably wouldn't be worth it.