I think some hosting providers limit the number of emails which can be sent per hour. What if I exceed this limit?
For example, suppose the limit is 200 emails per hour. What will happen if I send 250 emails in one hour?
1. Will only the first 200 emails be sent and the additional 50 emails be blocked?
2. Will my account be blacklisted as a spammer?
3. Will the server queue the additional 50 emails so that they are sent later?
I am developing a PHP application for a client and he needs to send out newsletters to subscribers.
You have to ask the hosting provider for a better understanding how they restrict the email. As far as I know, they will not delete your email instead, they queue the rest of the email to the next hour for sending out.
Maybe you can code in the way that every hour, it will send out around 150 email first. So that the client can use another 50 limit to send their own email, you never know when they need this 50 email to send out urgent stuff.
some of the provider directly block the connection and causes end user's mail client to prompt out those annoying messages. There are pros and cons of implementing this and depending on how you interpret it.