I noticed a new phenomena on Twitter yesterday. I got email notifications from bogus account names that my Twitter account is being followed.

Obviously the first thing one does is checking what user is following you and the only message one sees is a commercial ad.

Here's what I got on my Gmail account:

Maybe Twitter's user account registration system is being "worked on" by hackers or someone was doing this manually, but this definitely is able to put some message and link through.

Maybe Twitter should implement reputation-based mechanisms with Report Spam buttons to their system just like ISPs do. Spammers are trying to appear at every possible place with eyeballs and Twitter definitely has a lot of them.

Did you receive any similar "follow" notifications?

We got informed by one of our customers that he got removed from his own newsletter and our logs stated that the reason was the feedback loop. We’ve begun to analyze the content of the complaints and it has turned out that Yahoo had started to a add couple of headers to their messages.

Here’s a sample:

X-IP-SENDER: 98.136.44.45
Received: from [216.252.122.216] by n77.bullet.mail.sp1.yahoo.com with NNFMP; 27 Oct 2008 03:48:09 -0000
Received: from [69.147.65.166] by t1.bullet.sp1.yahoo.com with NNFMP; 27 Oct 2008 03:48:09 -0000
Received: from [127.0.0.1] by omp501.mail.sp1.yahoo.com with NNFMP; 27 Oct 2008 03:48:09 -0000
X-Yahoo-Newman-Property: ymail-5
X-Yahoo-Newman-Id: 939505.70691.bm@omp501.mail.sp1.yahoo.com
Received: (qmail 63926 invoked by uid 60001); 27 Oct 2008 03:48:09 -0000
Message-ID: <20081027034809.63924.qmail@web46108.mail.sp1.yahoo.com>
X-YahooUserId: REDACTED
X-YahooUserIP: 124.13.176.52
Date: Sun, 26 Oct 2008 20:48:09 -0700 (PDT)
From: yahoo mail bot
Subject: NOTSPAM: Top Dog Trading Video #2
To: notspam@mailservices.yahoo.com
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii

The Subject and To fields are most interesting. The Subject has the original message’s subject prefixed with “NOTSPAM:”. The To field seems to match the subject. After noticing this we started to browse different complaints. It turned out that after since October 25th the majority of Yahoo complaints has those new headers present.

Except the notspam@mailservices.yahoo.com address we found out that some of the complaints had the To set to possiblespam@mailservices.yahoo.com.

The notspam@mailservices.yahoo.com email address was added in the To field only between October 25th and October 30th. We have checked this across multiple servers. We still see some amount of the possiblespam@mailservices.yahoo.com in the To field and it seems to be the new standard as the number of messages with the old header-less format is minimal.

The question this brings up is whether Yahoo hasn’t sent us the data of people that were clicking “This is NOT spam” and instead of removing those email addresses from the list we should restore them as they were actually good subscribers. I’m talking about the interval between October 25th and October 30th.

Some of our customers and industry specialists reported that there was a drop in the average number of complaints coming from Yahoo’s feedback loops at the end of October. After a couple of days things went back to normal. Maybe this has also something to do with this. Obviously they were making some substantial changes in their system.

I just wouldn’t like if our customers lost some good subscribers because of this.

Has anyone noticed similar behavior and got similar reports from your customers? It would be great if the Yahoo team could make an official statement for sender’s, so we would know how to react.

BTW: It would be a great to see, who clicked “not spam” – this is a clear indicator that emails ARE wanted, no just the ones that are not

Yahoo kept their word.

We have posted a Yahoo FBL request for our customer
on Monday and the FBL was granted the same day!

A wonderful news for all marketers that have setup
new services after the Yahoo FBL was taken down.

Apply slowly not to swamp the Yahoo team.
They surely are busy guys.

Keep up the great work Yahoo!

A few days ago, I posted a comment on a Yahoo delivery issue I encountered. A few persons emailed me to have more info on how we solved this issue at m--x--m. This is the purpose of this post. I will describe how a new company overcame recent delivery issues with Yahoo Mail. I hope this will be useful to others.

Context
I am an engineer for m--x--m, a new email delivery company. We use a number of new ways to deliver emails and we mostly focus on transactional and newsletter emails.

Problem
With no increase in deliveries, nor in user complaints (as inferred from other FBL since we could not get one from Yahoo), we got completely blacklisted on Yahoo with the following message.

Aug 31 14:06:36 dserv128-mtl3 m--x--mail/smtp[8516]: 4D7F314C86A3: host e.mx.mail.yahoo.com[216.39.53.1] refused to talk to me: 421 Message from (xx.xx.xx.xx)temporarily deferred - 4.16.50. Please refer to http://help.yahoo.com/help/us/mail/defer/defer-06.html

We kept having this message and sometimes some messages were delivered... directly in the junk folder.

Therefore I started investigating and understood a few tricks.

What I have understood so far
Some of this points may be out of date. Please share with us any of your insight in the comment.

1. Yahoo does not offer anymore a FBL. This is the root of most issues.


2. Yahoo's filtering system is not compatible with the way most MTA handle their retries. In practice when a minor delivering issue arises, it can sometimes blacklist completely the IP.
   
3. Yahoo uses the following graduation when dealing with a temporary blocked IP:
   
   

   [TS01] -> [TS02] -> regular deferred message. (you will find these messages in your logs)
   
   

   Your goal is to stay at TS01. I did not find a way to go back from TS02 to TS01, so be careful.



4. When encountering a serious delivery issues, Yahoo wants you stop delivering for four hours. Doing so seems to reset Yahoo's « reputation counter ».


5. It seems Yahoo signals sometimes user complaint even without FBL. This happens when you see a « deferred » error message only for a specific user (while other emails to the same MX are still delivered).


6. Yahoo ends the block progressively, you can send before the end of the four hours but you take the risk to reduce your reputation.


7. Yahoo filtering algorithms seems to be of the form number of user complaint per unit of time -- as opposed to a percentage formula (like Hotmail for instance). For instance, 100 user complaints might trigger a block even if they happened on 100 million emails.

In a nutshell, Yahoo asks for a very specific way of handling delivery. Misconfigured MTA can actually cause a permanent block; the problem is most MTA are configured not to respond well to their temporary blocks.

Solution
I wrote a MTA dedicated for Yahoo delivery (our delivery architecture is very flexible in this aspect). Its main points are:

1. When presented with a 4XX.*deferred error, it equates it to a user complaints.


2. When presented with a TS01 message, it stops delivery for four hours on this MX DNS (but it keeps going on the others).


3. It smoothen deliveries so there is no burst (which might overcome the user complaint quota).


4. It uses a cluster of « smart shared IP » to ensure delivery even when temporary blocked.


5. It uses a smart backoff algorithm to increase a lower user complaint per unit of time.

This solved of all issues and even now we keep using this solution. If you encounter further problems with Yahoo, please let us know, we might be able to assist you.

This post was written in collaboration with Krzysztof Jarecki and Nicolas Toper (http://www.m--x--m.net) based on an idea from Krzysztof.

It is rumored that Yahoo is using some new reputation services that feed data into their filtering systems. Some people around are reporting odd behavior with Yahoo sends. I wanted to ask if anyone sees any impact on the delivery?

There were also rumors that Yahoo will partner with Return Path... Maybe it's that misterious reputation monitoring service?

There is a very lively discussion going on today at the URIBL's discussion group. It shows that although the email space seems to be a mature one there is still a lot of different interpretations of some basic terms. This may lead to misunderstandings and thus problems with solving blacklisting issues.

What could be witnessed today at URIBL was a marketer that was trying to remove his domain from the blacklist and he used the term "double opt-in" referring to his subscriber acquisition process. According to the representatives of the blacklist this term is "spammy" and the only valid term is Confirmed Opt-In or Closed-Loop Opt-In (COI).

This seems to be a typical approach among blacklists as SpamHaus is even publishing some definitions and what SpamHaus finds spam and ham.

Bottom line: to avoid any misunderstandings during conversations with blacklists' representatives proper terms need to be used

Another thing that is really radical is that blacklists go "easy" and simply skip what marketer's refer to as single opt-in. When someone fills in the opt-in form and wants to receive some newsletter it is perfectly legal to send it to them without confirmation (in USA of course, some countries may differ). Blacklists seem somehow to ignore this fact and assume that any email without confirmation is harvested. A lot of marketers using single opt-in have better email practices and results (especially in terms of relevant emails and low complaints) than people that do COI. This means that their emails are welcome by their beholders. This is the ultimate point and it's presence is somewhat invisible, when looking at the blacklists.

As a conclusion I think that there should be some cooperation opened between organizations like MAAWG, ESPC and the major blacklists to cover all aspects and create an understanding between legitimate marketers and blacklists that both hate spammers.

Any thoughts on this from fellow delivery experts?