Sending Email Broadcasts

Question

I'm working on an application that will allow management to send registered users (opt-in) broadcast emails at regular intervals, or based on various other criteria. In any case, I'm curious as to whether I should send a separate email to each recipient or bcc all of them on a single message. Currently the email list would be about 1500 recipients, but it should scale all the way up to at least 25k without problems.

Thoughts? Am I getting into a range that I need to worry about being put on spam lists?

Answer 1

You are getting into that range. This is the point where I would look to get a third party to send the email on my behalf. Let them worry about being marked as spammers, supply the bandwidth, etc.

Answer 2

Yes, I've had spam list problem with mailing lists of that size, managing email lists for non-profits.

One wants to take extra precautions: make sure your email has SPF records, write a script to send the emails in batches, paced out over time. Definitely send them one one at a time, not as bcc, as direct mail has a better chance of arriving. Make it very easy to unsubscribe. Include people's subscribed email in the message sent -- often people have email forwarded to another account and then try to unsubscribe that account and get frustrated.

Even so, don't be surprised if you have to change your IP at some point.

Answer 3

I recently built an application with those same criteria. We do the emailing in-house, and send one email to each recipient.

Do use domain keys signing or be sure to use SPF records for your domain. We didn't do that at first, and were blacklisted by a number of different ISPs. Fortunately, it is fairly easy to get them to unblock you. Most will include an online form you can fill out or an email address you can use in the server bounce message.

Answer 4

Don't try to implement the actual email sending yourself. That's a huge waste of time. Either outsource the entire process to one of the many reputable vendors out there (Many organizations I deal with use Constant Contact, and it works well), or run a garden-variety mailing list server (e.g. Mailman) in-house.

Either way, take efforts to make it very easy to unsubscribe (good vendors have that covered), to authenticate that messages are from your company, and to show that your company is not spamming. Real mailing list server software supports all of these goals, by adding proper headers that identify the source very clearly and making unsubscription easy. For instance, Gmail will now offer to send unsubscribe requests in response to mailing list messages marked as 'spam', as has AOL for a long time.

Definitely set up SPF and DKIM if you can manage it.

Finally, whatever you do, make sure you keep logs of your subscriptions, so that if someone does accuse you of spamming, you can defend yourself.

Answer 5

The task is mostly uninteresting on a strictly technical level. You should worry about what happens when a recipient thinks that your list's content is spam and starts (a) complaining or (b) flagging the message as spam with one or more anti-spam service providers. Something like this is bound to happen with a list of the size you describe.

If you are prepared and have the time handle such cases, go for it, at least for a start. (Changing your mail server's IP address as Devin Ceartas suggests won't be of much use by the way.)

If you want to build your own thing, I have two pieces of advice:

1. Unsubscribing has to be easy, no more than one or two clicks. Using Mailman or any other mailing list manager that was intended for discussion mailing lists is asking for trouble.
2. BCCing the same message to 1500 (or 25k) recipients may take some load off your mail server, but it has one serious disadvantage: You won't be able to use VERP in order to determine if all addresses that have once been subscribed to your list are still valid. (Large mail providers tend to classify messages as spam if there are delivery attempts to many invalid addresses.)

Answer 6

Ok, I guess I wasn't logged in when I created this. I'm not really worried about tracking at this point because it isn't a long term mailing list - by October the event this is for will be over with and the emails will be irrelevent until next year (when they have to re-opt in again). I think I'm going to try batch BCCing groups for right now and see how that works, and if need be I'll come up with a workaround.