If you are going to send emais to 3000++ users. Will you still use php mail function? I heard, it was not secured enough. How do I send a secured blast emails? I dont want t
When it comes to blasting emails, 3rd party implementations are fine but really it's not difficult to write your own. Basically you need to have PHP queue blast jobs in a db and have a service or a daemon polling every so often to see if there's work to be done. If there is it will send the blast out in chunks.
As far as "secure mail" there's really no such thing. If you need to alert users to sensitive data do what banks do. Send out an announcement telling the user simply to log into their account to view a message on the web site.