Word to the Wise

We make email better.


We make email better.

Word to the Wise helps email marketers create more effective email messages, programs and infrastructures. We advise you how to skillfully navigate the constant business, technology, and policy challenges so your messages reach your customers.

We can help you with your email strategy, deliverability challenges and many other email issues.

Latest stories

Answers to your questions about the new Yahoo and Google technical requirements


On January 9th at 6pm GMT, 1pm EST and 10am PST I’ll be speaking with Nout Boctor-Smith of Nine Lives Digital about the new Yahoo and Google technical requirements. In this webinar you’ll: Learn more about what these new email sender guidelines entail and how they differ from the status quo  Understand why you’re being asked to do things that were previously handled by your...

About My Email


Happy 2024, everyone! We’ve released a shiny new tool to let folks self-check a lot of common questions we see about email requirements. Go to AboutMy.email and send an email to the email address it gives you. Once it receives that email it will go through it and do many of the basic checks we’d usually do to check the technical health of a client’s email1AboutMy.email is a...

Tis the Season



I apparently gave chess.com an email address in 2007 – probably due to a client engagement? I don’t know. I unsubscribed from their mail at some point as there has only been one email from them between 2010 and 2021. Maybe this time they’ll actually unsubscribe me.



Email supports TLS (Transport Layer Security), what we used to call SSL. Unlike the web, which split it’s TLS support off into a completely different protocol – https, listening on port 443 vs http listening on port 80 – SMTP implements it inside it’s non-encrypted protocol. A mailserver advertises that it supports this by having the word “STARTTLS” in the...

Customer subdomain authentication


EDIT: Now with a production-ready implementation I talk about more here. On Tuesday I wrote about using DNS wildcards to implement customer-specific subdomains for email authentication. As I said then, that approach isn’t perfect. You’d much prefer to have per-customer domain authentication, where each customer has their own DKIM d= and ideally their own SPF records, rather than...

Wildcards and DKIM and DMARC, oh my!


If you’re an ESP with small customers you may have looked at the recent Google / Yahoo requirements around DMARC-style alignment for authentication and panicked a bit. Don’t impersonate Gmail From: headers. Gmail will begin using a DMARC quarantine enforcement policy, and impersonating Gmail From: headers might impact your email delivery.…For direct mail, the domain in the...

Deferrals at Microsoft


If you’re seeing a lot of “451 4.7.500 Server busy. Please try again later” from Office365 this morning you’re not alone. Microsoft are aware of the issue, and incident EX680695 says: Current status: We’ve identified that specific IP addresses are being unexpectedly limited by our anti-spam procedures, causing inbound external email delivery to become throttled and delayed...

When Asking a Question


A lot of beginner questions about email delivery aren’t about broad strategies for success, or technical details about authentication, or concerns about address acquisition. They’re something like: My mail to $ISP is being blocked. How do I contact someone there? Asking a question to your peers about how to deal with a concrete problem you’re having is a great thing to do...

New Requirements for Bulk Senders


UPDATE: You need to authenticate with both DKIM and SPF. Google are circulating a new set of requirements for bulk senders on their blog. So are Yahoo. It’s almost like postmasters talk to each other or something. If you dig through the links in the Gmail blog post you can find this summary of what they’ll be requiring from bulk senders by February: Set up SPF or DKIM email...

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