I have spent quite a bit of time over the last few days working with new clients who are asking a lot of basic, but insightful questions about delivery problems. I have been trying to come up with a model of how spam filtering works, to help them visualize the issue and understand how the different choices they make change, either for better or worse, their delivery.
One model that I have been using is the bucket model. Spamfilters are like buckets. Everything a sender does that looks like what spammers do adds water to the bucket. Reputation is a hole in the bottom of the bucket that lets some of the water flow out. When the bucket overflows, delivery is impacted.
I think this analogy helps explain why fixing any technical issues is so important. The less water that is added to the bucket by technical problems, the less likely it is that the water from content filters will overflow the bucket.