The Entrepreneur's Guide to Email Delivery, Part 3

Note: this is the third post in a series on email delivery.

After ignoring this series for a couple of months, Garry from Posterous submitted my original post toHacker News a few days ago. Since a few people seem to have found it useful, I’ve got a renewed motiva­tion for hammering out a few more posts.

All of the major ISPs and email providers have some propri­etary methods of inter­acting with large-volume email senders. Most include a feedback loop, which notifies email senders when a recip­ient marks a message as spam. This post will help you get set up with the major web-based email provider­s—Mi­crosoft, Yahoo!, AOL, and GMail.

Microsoft Hotmail & Live Mail

Hotmail is still one of the largest email services out there, even though if you live in the Valley you probably know zero people who use it. Because it is such a large attack surface, Microsoft­’s spam filter (called SmartScreen) is pretty aggres­sive, especially with mail coming from IP addresses with no sending history. Fortu­nately, they’ve imple­mented two major programs to help legit­i­mate email senders get into the inbox.

  • Smart Network Data Services — SNDS gives you deliv­er­ability infor­ma­tion based on the IP of your mailserver. You’ll need a Hotmail account to use as your SNDS login. Fill out the access request form, and you’ll receive a verifi­ca­tion link in an email to abuse or postmaster@yourdomain

    SNDS requires a minimum volume of about 100 emails per day in order to give you any data. Once your IP is activated, you’ll get infor­ma­tion on how your emails are being treated by Hotmail, including data on the number of unknown addresses, complaint rates, spam trap hits, and more. See the SNDS FAQ for more detailed information.
  • Junk Mail Reporting Program (JMRP) – This is Hotmail’s feedback loop program. Fill out thisMicrosoft Support questionnaire after signing up for SNDS above. There will be a legal document signing process that you’ll have to go through, but once you’re set up, you’ll receive an email to a speci­fied address for every spam complaint from a Hotmail user. You should remove complaining users from your sending lists in order to preserve your sender reputation.

The Postmaster Services home page has more infor­ma­tion on both programs.


Yahoo! Mail is the largest email provider in the US. Unfor­tu­nately, their feedback loop program has been closed to new appli­ca­tions for a year or more—see this FAQ answer on the Yahoo! postmaster site for more details.

As of January 2009, your best bet is to first read Yahoo!’s sending best practices, make sure you comply, and then fill out the Bulk Sender Form. If you only send double-opt-in mail (ie, you’re not sending user-generated invita­tions), you may be eligible for their Whitelist as well.

If you happen to have any infor­ma­tion on the Yahoo! feedback loop process, please leave a comment!


Plenty of low-tech US users still use AOL mail. They make very clear their email sending best practices, much like the other providers. Sign up for the feedback loop here. If you only send double opt-in mail (again, no user-generated invites), you can sign up for their whitelist.


As befits Google’s philos­o­phy, there’s very little human input involved in their spam filter­ing. Here are the GMail bulk sending guidelines. If you do run into deliv­er­ability issues here, there is a support form to contact them as well.

I person­ally haven’t had many issues getting email deliv­ered to Google — as long as you set up SPF and DKIM correctly (see my previous post in this series) and keep your complaint rates low, your mail should go into the inbox.