Email Delivery Voodoo?

I haven't used them, so I can't recommend them, but I recently saw that Heroku has partnered with a company called SendGrid that does email delivery as a service. It might be worth looking into.

http://sendgrid.com/

Just go to AWeber, pay $19/mo, send unlimited emails with highest delivery rate in the business.

Yeah, many ISPs are wary of newer IPs with low volume. To avoid volume problems, you usually need to be sending from a server that delivers >10,000 mails a day. Also, check your logs. Yahoo uses the following graduation when dealing with a temporary blocked mail: [TS01] -> [TS02] -> regular deferred message. (found in your logs) Your goal is to stay at TS01. If you're experiencing significant deliverability problems, Yahoo wants you to stop delivering to them for four hours. (We wrote an article about this a year ago, they've since then instituted feedback loops, which we employ in our deliverability service CritSend , but they still help you demystify some of what Yahoo's expecting from your server: http://blog.deliverability.com/nicolas_toper/ )

You've recieved some really great setup advice in this post and the owocki article as well. Keep a tight monitoring on your delivery feedbacks and spam folder clicks when you can by keeping watch through the feedback loops others have listed for you here.

Feel free to contact me if you need some help going through those logs for other deliverability items, they'll tell you a lot.

I recommend Critsend, but I'm partial because it's run by a friend. Heard good things about them though !

http://www.critsend.com

Reputation for your IP takes time. Some providers are smarter than others about how long you need to establish a reputation. Google seems quick if you follow the rules. Microsoft and AOL seem on the slower side, we give an IP a few weeks to "warm up" its reputation. And you need to be active about handling bounces, spam reports, etc. from day one.

Sending rate is also a huge signal for some providers (Microsoft) and seemingly not for others. In our experience, if you send more than one email per second per IP to Microsoft over a few hour period, that IP is almost guaranteed to get put in the penalty box for a few days. Stay under the limit and adhere to the other guidelines in that post and you're fine.

If you're going to be sending at higher volume, use different IPs for "transactional" mails -- signup, password reminders -- than for monthly mailings, etc. This way you protect the reputation of the IPs sending the stuff you really need to get through. (In all cases, you better be sending mail to registered, double-opt-in addresses, otherwise look in the mirror, you're a spammer.)

Also as another poster stated, sign up for the feedback loops. Some are a huge pain (Microsoft), some are very straighforward (Yahoo).

  http://feedbackloop.yahoo.net/
  http://postmaster.aol.com/fbl/fblinfo.html
  http://postmaster.live.com/Services.aspx#JMRPP
  http://feedback.comcast.net/

The return path sender certification will help with inbox placement but you have to maintain good reputation (low spam and bounces). If you are on a dedicated IP it will take some time for the reputation to improve...give it time. But if your spam and bounce rates are high it will never improve.

Also signup for hotmail sdns and fill out the yahoo bulk email sender form. hotmail sdns can help you figure out where your issues are with hotmail. filling out the bulk sender form will help with placement at yahoo. Its all about maintaining a consistent and good reputation...so if people are not marking your mail as spam and you aren't bouncing lots of email your reputation will improve over time.

Since you are doing this on your own I am assuming you want to continue down that route but if you want ESP recommendations contact me offline so I can learn more about your situation.

Yahoo / Hotmail may just be temporarily deferring your email rather than rejecting it outright. That list you mentioned is good, seems to have covered most of the important stuff. You might also want to make sure your mail server's IP address is not on any of the black lists. The following is a link to a perl script intended to be run from nagios that checks the following blacklists: dnsbl.sorbs.net, list.dsbl.org, zen.spamhaus.org, fulldom.rfc-ignorant.org, bl.spamcop.net, and blackholes.mail-abuse.org

http://pastebin.ca/1694024