Spam Resource: All Things Deliverability

My friend Dan Stevens (who founded email verification platform Kickbox and hired me there once upon a time) has rejoined the email community! After seeing him announce unMTA , I invited him to author a guest post here to share thoughts about his new venture and what his goals …

What happens if you choose the wrong subdomain? Does everything explode and the submarine sinks to the bottom of the ocean? Not really, but there are indeed some considerations around choice of subdomain for your various types of email messages. I recently tackled this topic in…

I recently sat down with a bunch of new friends to sit for a podcast recording. The podcast, Email’s Not Dead , is “about how we communicate with each other and the broader world through modern technologies.” Joining me on this adventure? Jonathan Torres, Eric Trinidad, Thomas …

Looking for an easy way to validate that your email is configured correctly? While technical compliance is only part of the deliverability equation (don’t forget our old friends reputation and engagement), it’s still very, very important to make sure you get it right: DNS confi…

Hey, you! Are you looking for work? It’s rough out there, I know. I want to help, if I can. Every now-and-then I’m going to share a post that highlights the name and focus areas of a smart expert in the email space who is looking for work. My goal is to assist with a bit of ext…

Well, since this song was originally released (in 2001) the future has indeed been movin' on. I don't know that I have any sunshine in a bag, but even lacking that, it was still great fun to see Gorillaz on SNL last week, and I rather enjoyed this little bit of time tr…

Like Gmail tabs? Want their categories to trickle down into your email client, if you’re not using Gmail's email client? Do you ever wish that the categories would show up as IMAP folders in Thunderbird? If you’ve answered yes to any of these questions, this clever hack mig…

I had a lot of fun joining Validity's Guy Hanson and Danielle Gallant recently, in our Litmus Live session, where we spoke to the topic of where email marketing is headed in 2026. And we covered a lot in that 30 minutes: deliverability trends, AI in the inbox, the future o…

Back in September 2025, I posted about receiving notice from Yahoo that they were apparently reducing the amount of space granted to Yahoo Mail user mailboxes from 1 terabyte to 20 gigabytes. (In hindsight, I now realize that this specific new limit might be US-specific.) Whil…

January and February were not kind to many email senders and mailbox providers. Glitches were to be found and experienced. Google accidentally misclassified a bunch of emails at one point. Yahoo and Apple seemed to be accidentally rejecting non-spam messages for a time. And Mi…

Yahoo has added new, additional sending IP addresses for their outbound email, as they recently announced on the Mailop list and elsewhere. Head on over to the “ Outbound Mail Servers” page on the Yahoo Sender Hub , or pick apart their SPF record , to find the most up-to-date…

If you're sending mail to subscribers in Japan, you need to know that the Goo mail service is no more. Goo has been around rather a long time. Owned by NTT Docomo, it has existed in some form or another since May 1999 , though I'm not exactly sure when email service was…

Are you curious about the current state of DMARC in 2026? Want to learn more about the adoption of email authentication and domain protection, who out there are putting their best foot forward to prevent phishing and spoofing of their important email domains? It's something…

Seeing rate limiting deferrals at Microsoft OLC (Outlook Consumer/Hotmail) domains ? Specifically with this error message: 451 4.7.650 The mail server [IP Address] has been temporarily rate limited due to IP reputation. For e-mail delivery information, see https://aka.ms/postma…

Look what I just found in my email. It's an email from staff AT hotmail.com: You are receiving this message because your sender IPs are enrolled in the Junk Mail Reporting Program (JMRP). We are modernizing JMRP by rebuilding the service on a new platform. Going forward, pr…

I saw somebody recently say that one of their biggest fears about starting a newsletter is that CAN-SPAM (the US federal anti-spam law) requires that you have an address in the footer and that it has to be legit, else you can (supposedly) get hit with a $50,000 fine. And also …

We’re starting a new feature here on Spam Resource: The Newsletter Spotlight! I’m a big fan of newsletters — they’re one of the best things about email — and I thought it would be fun to every so often highlight a newsletter that I’ve heard about, stumbled upon, actually subscr…

Here’s a long overdue updated snapshot of BIMI sender logo DNS records as found in the top ten million domains data set (the domain list from host.io , where I query and log a bunch of DNS records for every domain, every month). By adjusting the view on my Wombatmail BIMI data…

Josh Nelson is the CEO of Civic Shout , an ad platform built to help progressive causes reach supporters who actually want to hear from them. Earlier in his career, Josh ran major email and digital programs for groups like Al Gore’s Alliance for Climate Protection and CREDO Mo…

I’ll be co-presenting in a session at this year’s Litmus Live , peering into my crystal ball alongside Danielle Gallant and Guy Hanson from Validity. Join us for this free, virtual event! Our session on February 11th will see is sharing our thoughts on emerging trends, technolo…

Every so often someone emails me a screenshot from their inbox and asks a simple question: Is this a BIMI logo? A lot of the time, the answer is no. In my latest Ask Al video for Valimail , I walk through five logo, avatar, and profile picture mechanisms that can look a lot lik…

SmarterMail is an email/collaboration suite of tools positioned as a Microsoft Exchange alternative, offering native MAPI support, supposedly making it easy as a drop-in replacement for Microsoft's tools. If you use SmarterMail, it's important that you immediately ensu…

Koli-Lõks provides visibility into bulk email traffic, tracking sending IPs and domains to show how email is sent and on behalf of whom, with a focus on ESPs, ISPs, and other large email sending platforms. The email traffic data they collect is used, for among other purposes, t…

Ouch, what a click-baitey headline. But let’s run with it, because it comes from an honest place. As I mentioned here and elsewhere, I recently teamed up with Scott Ziegler from Valimail for a webinar digging into SMTP rejection data provided by Google starting in July/August …

Times are tough right now. Let's remember to be kind to each other. Youtube link