Hello friends, how are you?
I have more than 30000 users at our university and sending messages for all of them via bulk e-mail is too slow.
So, sometime ago I did a solution for an application to save the outgoing e-mails in a database and setup a cron job to send them in packages, just to avoid anti-spam rates. It worked so well and I'm using it in another applications too. I also save the cron jobs to the database to see some ougoing statistics like emails per second, number of emails sent, emails with errors, etc.
My idea is to add this feature to Moodle, saving all e-mails to the moodle database and use an scheduled task to send them in packages. Forum already have this feature, but it´s a great idea to setup this for all e-mail jobs.