The Interactive Advertising Bureau has a great deliverability guide available here as a free download. It’s 14 easy-to-read pages that anybody can understand.
I just read through it, and think it’s an excellent guide for increasing your email deliverability (whether you’re an agency or not, it’s very useful). Some of the topics it covers:
- Main causes of deliverability issues
- The 7 primary ways email gets filtered
- How to tell if you’re having deliverability problems
- How you can improve deliverability
- How to reduce spam complaints
Here are some random snippets from the report that I liked:
- "According to a 2004 DoubleClick study, 72% of people think that
hitting the "this is spam" button in their email client is the best way
to unsubscribe from a list. This means that every time your customers
decide they don’t want your email, you are susceptible to complaints at
the ISP level…"
- "Deliverability itself is not a metric, nor is it something that can be tracked through a single metric. A series of metrics are used to measure deliverability." So don’t believe any company (even MailChimp!) if they brag about their deliverability rate. It depends on too many different factors, and there’s no single standard being used. Our customers who are interested in measuring their own deliverability can take advantage of a special offer from DeliveryMonitor (details here).
- "There is a tendency to point the finger to everyone other than in the mirror when looking at blocking issues. The truth is, though, that you control nearly every facet of blocking and filtering that happens after you hit the "send" button on your campaigns." The report goes on to list a few things under your control.
Not to toot our own banana or anything, but MailChimp has a few resources you can read about email deliverability, spam filters, and preventing abuse reports too: