It has been almost a year since our last SpamTitan status update and since then the number of emails that our SpamTitan cluster has processed has nearly doubled. To date our cluster has now examined over 135 million emails as can be seen from the chart below.

The overall percentage of clean messages has dropped from 36.8% to 35.7%. This indicates an even greater percentage of change over the past 11 months since these percentages take into account all of the messages that have been filtered to date.

If you compare this latest graph to the one prior you’ll also notice a reduction in RBL rejections. This is just a symptom of the messages being tagged as spam earlier in the filtering process because you can also see an increase in other front line rejections (SPF, HELO verification,  greylisting, etc.). Messages filtered out at this stage would never get to the RBL rejection stage. Continue reading →