Spam Pre-Tests, Revisited

We have continued to see issues with delivery to Comcast addresses, as well as with a few organizations, such as Universities and Non-Profits which probably use their own spam filters. In my testing on Litmus, I found yesterday that an HTML email which has a large (in this case, ~90%) quantity of text as content, will pass the Barracuda spam filter tests, but not the Postini tests. The very same email will also be delivered to Comcast subscribers. So it would seem a good rule of thumb is to assume that if your email fails the Barracuda spam filter testing, it will not be delivered (or not be fully delivered) to Comcast subscribers.

Also interesting to note: for yesterday's email send, I broke the Comcast addresses into their own list, and sent just the text-only version to those recipients. I had no Comcast delivery issues. These results tell me the problem is not with my actual content itself (i.e., there was not "spammy" wording in the email), nor is it within the links or link structure (i.e., none of the links was malformed, and the tracking automatically inserted in each link by our ESP was not causing problems), as the text version (not spam blocked) had the same links as the HTML version (spam blocked).

If you are suffering with Comcast blocks also, my suggestion to you is this: In the short term, try sending a hybrid version just for Comcast subscribers, similar to the old days of AOL, which combines text with very little HTML... or just send your text-only version. Doing so will ensure that those subscribers will at least receive some version of your message, rather than nothing at all.

Of course, this method is not an ideal long-term solution. Get the deliverability team at your ESP involved as soon as possible - they should have, or should establish, relationships with the correct people in charge at the major ISPs, and may offer valuable insight from past experience as well.