How does the mass mailer work? Does it send it through PHP? Just wondering because I have a mass mailer subscription at dynamicemailer.net and the emails go into spam. But when I did a mass mail through mybb it went into inbox.
It depends on the email provider. They have some mailing companies blocked for sending out too many emails, on MyBB it depends on the server I believe because if the IP is blacklisted then it might send all the emails to spam/junk.
My host is host gator. If I had 100k members and did a mass mail of those 100k members would they all get the mass mail in there inbox? Or would it go in spam?
It's impossible to predict, there's so many factors involved. There's nothing "will it or won't it" involved, for some it might, for others it might not. It depends both on your setup and their setup.
As long as you set the amount to run per page quite low I think you should be fine. At 100K members, and if my mathematics isn't so rusty, setting the amount to run per page to 50 should get the queue finished within 3 hours (assuming you're not running the tasks by cron, and taking in to account the task system relies on forum activity).
3 hours is more than enough. I could change it to a week as long as they make it into the inbox.
How do I prevent my server from being blacklisted? Does sending them in smaller batches help the chances of not getting blacklisted?
Also, does my hosting matter?