Why do ISPs do that?

One of the most common things I hear is “but why does the ISP do it that way?” The generic answer for that question is: because it works for them and meets their needs. Anyone designing a mail system has to implement some sort of spam filtering and will have to accept the potential for lost mail. Even the those recipients who runs no software filtering may lose mail. Their spamfilter is the delete key and sometimes they’ll delete a real mail.
Every mailserver admin, whether managing a MTA for a corporation, an ISP or themselves inevitably looks at the question of false positives and false negatives. Some are more sensitive to false negatives and would rather block real mail than have to wade through a mailbox full of spam. Others are more sensitive to false positives and would rather deal with unfiltered spam than risk losing mail.
At the ISPs, many of these decisions aren’t made by one person, but the decisions are driven by the business philosophy, requirements and technology. The different consumer ISPs have different philosophies and these show in their spamfiltering.
Gmail, for instance, has a lot of faith in their ability to sort, classify and rank text. This is, after all, what Google does. Therefore, they accept most of the email delivered to Gmail users and then sort after the fact. This fits their technology, their available resources and their business philosophy. They leave as much filtering at the enduser level as they can.
Yahoo, on the other hand, chooses to filter mail at the MTA. While their spamfoldering algorithms are good, they don’t want to waste CPU and filtering effort on mail that they think may be spam. So, they choose to block heavily at the edge, going so far as to rate limit senders that they don’t know about the mail. Endusers are protected from malicious mail and senders have the ability to retry mail until it is accepted.
The same types of entries could be written about Hotmail or AOL. They could even be written about the various spam filter vendors and blocklists. Every company has their own way of doing things and their way reflects their underlying business philosophy.

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Define "spam"

A comment came through recently from Trent asking me to define spam. It’s been a while since I’ve talked about how I define spam, so let’s look at it.
Personally, I describe spam as unsolicited bulk email. If I didn’t ask for it and it looks like bulk mail then I consider it spam. In many cases the spammers have multiple email addresses of mine so I can demonstrate the mail was sent in bulk.
In my consulting and working with clients, though, I rarely use the word spam. There are so many different definitions of spam, I have no way to know if my clients understand what I am saying, so I avoid the term as much as humanly possible. An example of some of the few definitions of spam I’ve seen used over the years.

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Transitioning Yahoo bound email from Goodmail certification

In early February Yahoo announced they were no longer offering preferred delivery to Goodmail customers. By the end of March, Yahoo will have decommissioned the Goodmail specific mail handling servers. What does this mean for Goodmail customers who have no history of mail to the normal Yahoo mail exchanges? Will they have to go through an IP warmup period?
Thankfully, no, they won’t. IP addresses that have been delivering Goodmail certified mail are being transitioned across to the Yahoo whitelisting program. Just because customers are losing Goodmail certification does not mean they will lose all their sending history at Yahoo. This is very good news, as senders don’t have to give up all their sending history due to Yahoo’s decisions.
I have heard some grumbling from some delivery experts that the ‘pre-warmup’ isn’t meaningful or useful. I strongly disagree. The reason senders have to warm up IP addresses is because spammers are very good at finding unused addresses and exploiting them to send spam. The warmup period gives the receivers a way to evaluate the mailstream from a particular IP and determine if the mail is wanted without having to subject their users to excessive amounts of spam.
In this case, Yahoo knows that good senders will be moving from one set of mail exchangers to another. They have nothing to gain by forcing those senders to go through a warmup period. They know what the mailstreams look like and can special case them. This isn’t a benefit every sender gets, in fact losing established reputation is one of the major considerations when moving IP addresses, ESPs or certification services.
While current Goodmail customers are getting this benefit now, they will be subject to the same spam filtering other senders face at Yahoo. Failure to meet Yahoo’s thresholds for good email may result in loss of whitelisting, bulk foldering of email and rate limiting.
More detailed information about delivering to Yahoo is available on the Word to the Wise Delivery Wiki.

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Yahoo stops offering preferred delivery to Goodmail certified email

A week ago, Goodmail notified customers about upcoming changes to the Goodmail Certification program. They wanted customers to be aware that Yahoo was going to stop offering Goodmail certified email priority delivery and guaranteed inbox placement as of February first. I’ve talked with a number of people in the industry, including representatives of Goodmail and Yahoo about this change.
Yahoo was the first to respond to my request for a comment, and offered the following statements. The decision was made at some of the higher levels of management and my contact did not participate. I was told that Yahoo was looking to have more control over their incoming mail stream. They did not want to be contractually obligated to deliver email. The Yahoo rep also told me that Goodmail was in no way responsible for the Yahoo connectivity problems over the last couple weeks.
I also spoke with Goodmail. They also stated that Goodmail was in no way responsible for the Yahoo MTA problems. They are continuing to negotiate with Yahoo and are hoping to have full functionality to Goodmail certified email at Yahoo in the future. Also, Goodmail certified email may continue to see good delivery at Yahoo, but the certification symbol will not be displayed to Yahoo users.
I do believe Goodmail is continuing to negotiate with Yahoo, but I don’t expect to see any reversal of the decision any time soon. There are a number of underlying problems here, but reading between the lines it seems that Goodmail is certifying companies that send mail Yahoo users don’t want.
Last summer a number of people in the industry told me that Yahoo had a meeting with Goodmail and told Goodmail that the quality of the mail that they certified was not up to Yahoo’s standards. At that point, Goodmail dropped a number of clients and stopped taking on new clients. One colleague believed he had a slam-dunk application that would take days to approve. Instead he chased Goodmail sales reps for weeks looking for confirmation that his employer would be accepted. Eventually, he did receive a response: his employer was not accepted and there would be a full revamping of the qualifications for the certification program.
It seems, though, that any changes implemented by Goodmail over the summer did not improve the mail stream enough for Yahoo to continue outsourcing delivery decisions to Goodmail.
Quite frankly, I am unsurprised by this. My impression of Goodmail has always been they never really understood the role of a certifying agency. For any certifying agency to be successful, they must continually monitor certified customers and enforce standards. Goodmail’s initial certification process was fine, but they never seemed to follow through on the monitoring and enforcement. I remember sitting at lunch with one of their founders a few years ago and repeatedly asking the same questions: How are you going to police your customers? What are you going to do when bad mailers come to you? How are you going to enforce your standards? The answers I received were vague and left me with the opinion that they didn’t really understand what spammers would do, or pay, to get guaranteed inbox placement. I never felt they recognized the work involved in enforcing the high standards needed to keep their ISP partners happy with their service.
What distinguishes Goodmail from other certification services is that Goodmail doesn’t make recommendations to recipient ISPs. Instead, Goodmail partner ISPs are contractually required to accept Goodmail certified email and deliver that to the ISP. In this case, it appears the certified mail did not meet Yahoo’s standards, and Yahoo ended the contract. I don’t expect Yahoo to change their stance until Goodmail can convince Yahoo that Goodmail will treat Yahoo users email stream exactly the same as Yahoo does.

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