Well, it depends. We are in email marketing industry since 1999 and we receive the same question almost every day: “How much can send Oempro in one hour?”. The answer is easy: Ten thousands, even more on a standard server. But is this good for your email delivery rate?

Today, many email services such as Hotmail, AOL, Yahoo! and Gmail are running very complex filters against junk and spam emails. One of them is “number of emails that are received from one source at one interval” filter.

Let me give you an example: Let’s say you have 50,000 recipients pending in your email campaign. 40% of them are Hotmail email addresses. 30% of the rest are from Yahoo! mail, 20% of the rest from Gmail and the rest are regular POP3 addresses.

When you fire email campaign to those 50,000 recipients, if you send too fast, Hotmail and similar web based services will start blocking your delivery. They will temporarily “block” and return you an error message indicating that your delivery has been blocked and it will be resumed not later than 48 hours.

It seems better to send millions of email in 1 hour but it’s always better to control your sending performance and limit the sending with a few ten thousands such as 50,000 per hour (which is around 13 emails per second).

Of course, my suggestion is not feasible for “time-sensitive” email campaigns such as sending a discount coupon which will expire in 1 hour to 500,000 recipients. This kind of campaigns require more professional email server setup environment.

Always keep an eye over your subscriber lists. Always know which email services are being used by your recipients and adjust your delivery rates based on those popular services in your lists.

In Oempro, you can generate email service usage break-down statistics for your lists. This will definetely help you.