Firstly, I AM NOT A SPAMMER :) I am a legitimate developer, working for a company who is currently developing an enewsletter sending system for our clients.
Now, we sent out a campaign for one of our clients to 80k solicited emails, and we got a huge amount blocked due to spam, even though our client has used ymlp.com to send similar campaigns to the same mailing list in the past with no problems.
I have stumbled across a few nuggets of information such as:
How to send 100,000 emails weekly?
http://www.codinghorror.com/blog/2010/04/so-youd-like-to-send-some-email-through-code.html
So I have got the SPF record setup, and I am in the process of sorting out DKIM records too.
But my question is this... How can ymlp.com and other newsletter sending systems such as campaign monitor and mail chimp get by all the spam blockage, without getting their users to setup these DNS records?
Our client who uses ymlp.com has no other SPF records setup other than the one I have created for our system.
I have noticed the word spammer being thrown around way too freely in topics such as this, so again I must reiterate, I am not looking to spam people, this is a genuine question for a genuine system in development.
Edit: - We seem to pass all SPF / DKIM / DomainKeys checks ( brandonchecketts.com/emailtest.php ), yet still get rejected for spam by a fairly hefty chunk. Our read rate on campaigns sent is about 2% at the mo, which is way below the 7-8% we expect
Have you checked out reverse DNS? It does help on the deliverability front. Also, be sure to monitor the reputation of your IPs.
Hope that helps!