I am not a doctor, but Spam is like diabetes, its a progressive illness. The longer you have it, the worse it gets. This may sound anecdotal, but its true. At Quonix, we have been filtering email for people since 2000. Some of customers have great results and they get very few junk emails to their inbox, yet others still get 20-30 junk emails post filter.
Why is there such a large variance in spam filtering performance?
The amount of time your business has lived on the internet directly effects the total amount of junk email targeted towards you. We have customers that have been online using the same emails for over 10 years, and we have some customers that just came online last year. Those 10 year customers will always have a large amount of spam slipping through the filter. Even if we block 99%, because of the age of their “progressive” illness, they are exposed to more daily email prior to filtering? We have some users that get 1000 emails a day, even with 99% effectiveness, they will still get 10 junk emails to their inbox.
Alas, there is a cure!
Its sounds obvious, but most fixes are. Change your email address every few years and never publish it. Its not that bad, trust me. For customers that have chronic spam issues, we recommend they re-issue all users new email addresses. The old email addresses we leave active, but we have them return an aut0-response that simply states that this address has been modified and you need to contact us at the number below to obtain the new address. After a few months, the old addresses are deactivated. The new address schema is now “clean” and will remain clean for a few years.
Switching to another filtering product will not solve the problem, it will only waste time and money. Bite the bullet, and change your addresses! It will be well worth the initial headache.