Derek Harding has a pair of articles on ClickZ about Gmail giving their users information about why a particular email message was filtered.
What Gmail Teaches Us about Spam Filtering
Gmail Filtering: The Spam Disposition
Both articles are worth a read. They talk about what we know about Gmail and what we can infer from the data they provide to senders.
Yesterday Gmail rolled out some changes to their interface. One of the changes is that they are now showing end users authentication results in the user screen.
It’s really the next step in email authentication, showing the results to the end user.
So how does Google do this? Google is checking both SPF and DKIM. If mail is authenticated and the authentication matches the from address then they display the email as:
If we click on “details” for that message, we find more specific information.
In this case the mail went through our outgoing mailserver to gmail.
Mailed-by indicates that the message passed SPF and that the IP address is a valid source of mail from wordtothewise.com.
Signed-by shows the domain in the DKIM d=. In this case, we signed with the subdomain dt.wordtothewise.com. That’s what happens when you sign using the domain in the From address (or a subdomain of it).
For a lot of bulk senders, though, their mail is signed using their ESP’s domain instead. In that case Gmail shows who signed the mail as well as the from address.
And when we click on “details” for that message we see:
This is an email from a sender using Madmimi as an ESP. Madmimi is handling both the SPF authentication and the DKIM authentication.
As an aside, this particular sender has a high enough reputation that Gmail is offering me an unsubscribe option in their interface.
Gmail is distinguishing between first party and third party signatures in authentication. If the mail is authenticated, but the authentication appears to be handled by a separate entity, then Gmail is alerting recipients to that fact.
What does this mean for bulk senders?
For senders that are signing with a domain that matches their From: domain, there is no change. Recipients will not see any mention of your ESP in the headers.
However, if you are using an ESP that is signing your mail with a domain they own, then your recipients will see that information displayed in the email interface. If you don’t want this to be displayed by Gmail, then you will need to move to first party signing. Talk to your ESP about this. If they’re unsure of how to manage it, you can point them to DKIM Core for an Email Service Provider.
Gmail blogpost about the changes
Gmail help page about authentication results
As I’ve said before, I can usually tell when some ISP changes their filtering algorithm because I start getting tons and tons of calls about delivery problems at that ISP. This past month it’s been Gmail.
There have been two symptoms I’ve been hearing about. One is an increase in bulk folder delivery for mail that previously was reliably hitting the inbox. The other is a bit more interesting. I’ve heard of 3 different mailers, with good reputations and very clean lists, that are seeing 4xx delays on some of their mail. The only consistency I, and my colleagues at some ESPs, have identified is that the mail is “bursty.”
The senders affected by this do send out mail daily, but the daily mail is primarily order confirmations or receipts or other transactional mails. They send bi-weekly newsletters, though, exploding their volume from a few tens of thousands up to hundreds of thousands. This seems to trigger Gmail to defer mail. It does get delivered eventually. It’s frustrating to try and deal with because neither side is really doing anything wrong, but good senders are seeing delivery delays.
For the bulk foldering, Bronto has a good blog post talking about the changes and offering some solid suggestions for how to deal with them. I’m also hearing from some folks who are reliable that Gmail may be rolling back some of the bulk foldering changes based on feedback from their users.
So if you’re seeing changes at Gmail, it’s not just you.
ISPs are continually developing tools for their users. Some of the newer tools are automatic filters that help users organize the volumes of mail they’re getting. Gmail released Priority Inbox over a year ago. Hotmail announced new filters as part of Wave 5 back in October.
All of these announcements cause much consternation in the email marketing industry. Just today there was a long discussion on the Only Influencers list about the new Hotmail filtering. There was even some discussion about why the ISPs were doing this.
I think it’s pretty simple why they’re creating new tools: users are asking for them. The core of these new filters is ISPs reacting to consumer demand. They wouldn’t put the energy into development if their users didn’t want it. And many users do and will use priority inbox or the new Hotmail filtering.
Some people are concerned that marketing email will be less effective if mail is not in the inbox.