Vetting customers: an intro

I promised a couple weeks ago, pre-MAAWG, to write about screening new customers. Things have been a bit busy and I have not had a lot of time for the blog. However, today there has been a long conversation on one of the spam related mailing lists relating to ESPs and customer screening. This conversation inspired me to write this introduction to customer vetting.

I have designed customer screening programs for a number of clients as well as actually had an active role in some of those processes. I also screen my own customers and have taught other people how to vet customers.

When designing a vetting process a company must target the process to the size and revenue potential of their customers. If an ESP has a small number of customers, each having a very large recipient base, one single bad customer has the potential to affect the overall reputation of all the ESP customers. With large number of customers sending to very small recipient bases, then one single bad customer is not going to affect overall reputation as dramatically as larger senders will

Because the larger customers have an actual impact on reputation, it is really important to vet the customer. It’s going to cost money and some time, but responsible ESPs have to do it. Really good customers are going to be vetting the ESP at the same time. They don’t want to go with an ESP that has a poor reputation. It is much like dating, each party is assessing the other party and the suitability of a longer term relationship.

For the tiny mailers, though, there is a very small chance that one, single bad customer sending a single bad mailing will destroy the overall delivery of an ESP and ruin their reputation at large receivers. In this case, it makes a lot more sense, both financially and in terms of resource allocation, to screen the email address list rather than the individual customer. This can be mostly automated, with clearly bad lists being prohibited from being mailed and suspicious lists being kicked to humans for decisions.

Let’s be honest, anyone who comes to an ESP with a list of under 20K names is not a big time spammer trying to steal their reputation. Those are the easy ones to deal with, screen the list, limit the number of addresses that can be uploaded upload and limit, even if just by price, the number of mails that can be sent out during any period. Some ESPs really do cater to the small, community group market and they do tend to screen lists not customers.

For larger customers ESPs have a greater challenge. They must identify the real, legitimate mailers that have permission to send mail and identify the ones that are spammers attempting to steal an ESPs reputation. Spammers attempting to steal an ESPs reputation go out of their way to subvert the screening process. One of the hardest things about screening customers is getting the subversive ones to give an ESP enough information to make an informed decision about that customer. I will not lie, a subversive potential customer is expensive to screen, but that investment protects a sender’s reputation and the reputation of their other customers.

Another thing to remember about vetting is that no vetting process is going to be 100% accurate. ESPs with a good process can screen out 80 – 90% of the bad guys before a single email is sent. Most responsible ESPs do that and then stomp wildly on that remaining percentage that are evil or malicious.


  1. GotGuinness? says

    “and then stomp wildly on that remaining percentage that are evil or malicious.”

    I prefer to call it ‘discontinuing our current relationship’…Ah hell, what am I thinking, you’re right, have boots, will stomp.

  2. laura says

    Steve and I have this somewhat odd habit of watching PBS kids shows in the morning when we’re staying in hotel rooms. Recently, we saw a show that had a little girl named Jill knocking over a little boy’s blocks while singing “up the hill. up the hill. Stomp. Stomp. Stomp.” This is the song that went through my head as I approved your comment.

  3. DJ Waldow says

    @laura –

    I’m really glad you published this piece. At Bronto, we have a very similar vetting process as the one you outline above. It’s amazing what you uncover by asking some simple questions. We find that we typically have the most success (good deliverability, solid partnership/working relationship, etc) with new clients who are willing to explain their list growth processes as well as those who are willing to adapt.

    99% of clients we encounter *want* to do the “right thing,” but many have either been utilizing poor practices for so long or are coming from an in-house solution that was unable to remove hard bounces, unsubs, etc. Those clients who are willing to work with us, take our advice, load and send to their lists slowly, ultimately are better off in the long run.

    Love to hear what others are doing. Anyone else out there?


  4. Amran says

    Hi Laura,

    You are right about vetting the customers and all ESPs should be responsible to at least do some checking. At sendcube, we go through all the lists uploaded by our customers on top of checking all new paying customers. Customers who upload a list will not be able to use them until our delivery team approve them, wheather they batch import 1 or 1 million subscribers. During this process, we have seen quite an amount of lists which is obviously being purchased and of course most of the time, never get any respond from the “customer” when we enquire about it. Some are honest enough to tell you that they purchase them, get a telemarketers to get the emails and etc.

    The most classic case we had was checking on a customer who batch import over 30K email addresses and looking at them, it was an obviously purchased list. So my team email the customer to request for more information on how they got the list and they bluntly inform us that we are NOT a US based ESP thus we are not covered by the US spam law. So there is no reason why we cannot approve their list! Simply no words to describe this customer and yes, the customer is being block.

    Our stand has always been this, we rather help a customer who pay us $10 per month if they are willing to learn from their mistake than a customer who are paying us hundreds per month but are not willing to learn.

  5. Deliverability and what your ESP can do | The Marketr says

    […] Bronto has a vetting process for new […]


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