According to these Russians, They cracked the Yahoo Captcha and are giving away how they did it here.

The implementation of yahoo CAPTCHA recognition engine is here . It consists of two projects (client and server).
First project (server) needs MATLAB 2007a Compiler Runtime (MCR) installed. It waits for a connection and receives CAPTCHA, after that it sends recognized CAPTCHA text string back to client.
Client reads jpg-files in test1 directory and sends them one by one to the server located on the same machine.

btw, I have tested it.

PDFassassin is a module for SpamAssassin that allows for the scanning of PDF files in email message attachments. Email bodies are scanned upon connection and checked for PDF attachments. Text is extracted from the PDF via pdftotext and scanned by SpamAssassin. Should the PDF contain images, the gocr program is called to extract the text content. The total spam score of the PDF is compared against the global required_score setting; if it’s higher, a score equal to the one specified in pdf.cf is appended to the overall score of the email message.

With the recent torrent of PDF spam, we created a module for SpamAssassin that allows for the scanning of PDF files. The module, linked below this post, works in the following way:

1. Email bodies are scanned upon connection, and checked for PDF attachments.
2. Text is extracted from the PDF via pdftotext, and scanned by SpamAssassin.
3. Should the PDF contain images, the gocr binary is called to extract the text content.
4. The total spam score of the PDF is compared against the global required_score setting; if it’s higher, a score equal to the one specified in pdf.cf (default of 10) is appended to the overall score of the email message.

This approach is a departure from the usual method as it scans the content against the SpamAssassin engine, instead of using a word list filter.

Should you need to install the module, download it from: http://atmail.com/members/Pdf.tgz.

Installation directions can be found in the README file inside the archive.

PDFassassin forum: http://forum.atmail.com/viewforum.php?id=10

I just succeeded in applying Aol Feedback Loop(FBL) for my company a few days ago, and today I got about 9 “Email Feedback Report for IP xx.xx.xx.xx”, and “to” are all “redacted@aol.com”, I was confused who is “redacted@aol.com”? so I search google, and got a very important message from a forum, so I backup it here.

I just sent out my newsletter to my subscribers. A lot of them are AOL members so I signed up for the feedback loop with AOL so I know when someone marks my message as spam so I can remove them from my list. I can also contact them and ask them why they chose not to unsubscribe but marked it as spam instead.
So this is where my question comes in; who is redacted@aol.com? Is this some kind of aol bot? Because this email address has marked my message as spam like 15-20 times but when I tried to delete him from the list- I have no record of that email address.
Does anyone have a clue as to what is going on?
Thanks,
-Chris

Hi Chris,
It’s an aol bot. You get it whenever one of your recipients click the ever so convenient “this is spam” button displayed on every AOL message.
Another thing you should know -
Effectively mailing into AOL, Yahoo, Hotmail is not easy. Each mail server is different. AOL for example will automatically black list your IP Address (without telling you about it) whenever you send more than 3 email messages from the same IP address within 60 seconds and all messages have the same hash code (bulk mail).
If you’re sending less than 5,000 emails you should be okay, but anything above that number, go with an Email Marketing solution
(Disclaimer: That’s what we do)

So theres no way I can actually find out which users are flagging my message as spam?
There are wayyyyyyy too many people that are spam trigger happy. Its just as easy to click an unsubscribe link as it is to click a spam button.
I have a list of ~44,500 subscribers… 12k are yahoo, 9k are hotmail, and 8k are AOL.
Ive been looking into an email solution but I havent been able to find one that integrates with my vbulletin registration. Do you have any suggestions?
Thanks for the response Mike- I appreciate it
-Chris

Chris,
You can easily find out WHO is clicking on the this is spam button. That’s the whole purpose of the feedback loop. It’s designed for you to identify which ones of your users are reporting the message as spam so that you can remove these users from future mailings and identify the source (how they got on your list) so you can avoid it in the future.
With every message AOL sends you, they hide the recipient emailaddress but they include an ID of the message from your mail server. Depending on the mail server software you use, you can easily pinpoint that message based on the unique message ID and identify who the target recipient was.
If you ignore those messages, AOL (and Yahoo and Hotmail) will quickly blacklist your IP address. Yahoo does it for undeliverables. In other words, if you ignore Yahoo’s undeliverable messages and keep sending to these email-addresses, very quickly Yahoo will block messages coming from your IP address (without telling you about it) or automatically flagging them as spam.
We provide an API for bloggers and forum owners such as yourself, where instead of calling the local php mail() command, you call our API with the message from/to/subject/header/body. We transmit the message from our white-listed IP addresses certified by bonded sender and we handle all removes, undeliverables and spam complaints for you. We do have a plugin for vbulletin. The cost is one penny per email delivered. There is no cost for bouncebacks. Let me know if you’re interested.
If it’s above your budget, I would recommend installing a mail server that supports easy lookup of message from/to by message ID and manually removing users who report your messages as spam from your mailing list by taking them off the list.
PM me if you have any other specific questions and I’ll be happy to help.

Base on the guide, I removed all of them that report spam on AOL.
from: Who/what is redacted@aol.com? (spam blocking related question)