The email list hygiene industry has metamorphosed into two categories. Email validation and email verification. I have written several articles about the two separately on my blog, but I think it’s important to explain both processes in one article so you can choose which is right for you if you are an email marketer.
Email validation concentrates on external threats and some return paths (bounces). Validation finds and removes spamtraps, protestors, syntax errors, unicode characters, misspelled domains, incorrect strings, invalid and/or unlikely email characters, departments, erroneous mx, flawed domain setups and does IP threat matching to removal. Validation does verification to some degree but cannot validate top-level domains like Yahoo, AOL, MSN, Hotmail and the like (free email service providers).
Verification focuses all of its efforts on the return path itself, which can be a bounce address (hard or soft), an envelope from, envelope sender address, mail from or return address. In other words, when a sender executes a message, the recipient server could send a return response. In example: the mailbox is full, unavailable (such as not found), blocked, bad command, exceeded storage, failed transaction, syntax error, counter argument, requested action not taken and/or insufficient system storage or out of office reply just to name a few. There are dozens of return paths and in my next article I will list and explain all of them.
Ok, thanks for the explanation, James, but which of these two processes should I use? Good question. Validation would be needed for third party and/or old lists. Third party lists are traded, leased/rented or sold to where the list owner isn’t familiar with it. This industry practice is considered gorilla marketing and is frowned upon, also said to be illegal according to some spam fighters. If your list falls in this category, be extremely careful and upfront about it when questioned by your ESP. The truth gets you far.
Old lists are the most common that we scrub and are quite dangerous. For example, if your list is over 5,000 and you allowed it to sit for a month or two, you just made a colossal mistake. There are hundreds of articles explaining why you should constantly be emailing to your list and why, but they don’t get into the deeper reasons. Spam fighters have, in the past, purchased expired domains. The odds of your list containing an expired domain are pretty high. And the odds of that domain belonging to a spam fighter increases with the amount of data you have.
Even though expired domain traps are extremely important to remove, return paths and protestors are the leading cause of email service provider suspensions. You do not want to let your list age, period. Without getting into all of the details of why an email turns into a bounce, let it be known that bounces grow faster than you think. In example, 30% of emails are lost each year to normal attrition. If we divide that number between 12 months, we get an average of 2.5%. Depending on your email service provider, this is a high number and each has their own thresholds under their policies and procedures. If you upload a list or send to it after just 30 days, you may get several warnings of either suspensions or requests to clean it up.
So in closing, which is service should you use? If your list has not been mailed to within the last 3 – 4 weeks, all you would need is verification. But if your list is older than that, you need both. Even though validation does a great job of removing bounces, it doesn’t remove top-level domains as explained above. You will need verification to remove those false positives.