Spring is a Wonderful Time of Year

Posted by Melinda Plemel on

Spring is a wonderful time of year. Winter clothes are put away, baby birds are singing, flowers are blooming, and people are cleaning house.

Maybe you’ve heard the term, spring cleaning? It’s an annual tradition of cleaning house from top to bottom that usually takes place during the first days of spring, hence the name. It’s also used often in business; for example, you’ll see the term spring cleaning in email marketing. There are hundreds of blog posts offering advice to email marketers on how to clean their email list, from monitoring who is the most or least active to updating content and templates. However, there isn’t much information when it comes to the other side of the email industry: mailbox providers.

I’m sure the question has crossed your mind (especially when you see an unexpected spike in invalid bounces): do mailbox providers spring clean?

How do mailbox providers spring clean?

First, what does spring cleaning mean for a mailbox provider? I have been asked on several occasions if a mailbox provider is cleaning out their invalid accounts and bouncing all invalid accounts at one time. Well, that isn’t quite how it works.

I know there are a few exceptions to the rule, like when Yahoo decided to do the email reclaim project. They reviewed accounts and did a mass-bounce so senders could clean their list before an address was available to be reclaimed. But for the most part, there is never a mass removal of accounts; it just doesn’t work that way.

Most mailbox providers have a process that is ongoing, sitting the background. There are many factors MBPs take into consideration before they decide to deactivate an account, and the process’ of free webmail services and MBPs that provide paid accounts are different.

For free webmail providers, the biggest consideration is how long has it been since the end-user logged in to the account. Many MBPs will keep an account for many months to a year of inactivity before they start the process of deeming this a dead account. Once an email account is considered inactive, the MBP will send an error code (usually a 550) indicating that message will not be accepted and the account is inactive. According to Microsoft, they will allow the account to be dormant (hasn’t been logged into) for 180 days. At that point, they will begin to send 550 error codes indicating the account to be inactive.

It’s a bit different for a paid service. Basically, the account will remain open as long as you pay your bill. Once the subscription is canceled, the account is turned off, and the ISP may keep your mail for a certain amount of time in the event you reactivate. After that time, the ISP will send out a bounce code letting email marketers know to remove this address from their list.

Why should senders spring clean?

Okay, so MBPs don’t really “spring clean,” but that doesn’t mean you can ignore those occasional spikes in inactive accounts. You should certainly consider these to be legit, follow best practices and remove them from future mailings. Keep in mind there can be a risk to your IP/domain reputation if you choose to ignore inactive bounces over a period of time. Not only can sending to inactive account hurt your reputation, it can also have a negative effect on your active list of subscribers.

For example, if you continue to send to inactive/dead accounts, after a while your mail could begin to bulk. Then,you are unable to reach your active subscribers, they will stop engaging with your mail and the filtering systems at the MBP will assume the mail is being delivered correctly. It becomes extremely difficult to change that disposition and get back into the inbox.

Another possibility is hitting spam traps. While some of the bigger MBPs may not recycle accounts into spam traps, there are still many providers that do. Of course, this isn’t something that happens overnight. You would never see a 550 inactive bounce and the next day it’s a spam trap. All MBPs and ISPs that use recycled accounts will condition these for a period of time, typically 6 months. The MBP will send out a 550 bounce code first, giving the sender the opportunity to remove the address. After at least six months, they may choose to recycle continue to bounce. It’s impossible to know, so it’s better to be safe than sorry and remove when you first see the bounce.

I know this is easier said than done in many cases. Email marketers are faced with many challenges when it comes to removing any addresses from their database, so what to do? If you are hesitant to remove 550 inactive addresses when you see a spike and you really just want to make sure, then do a test.

If you have the ability to separate these accounts to a different IP, you can test to a handful to see if they bounce again. Keep in mind, this does come with some risk, so make sure to really plan out the test. If you are hesitant to possibly burn an IP’s reputation, then mix a few into your active list and send. If you see another 550 bounce, then bite the bullet and remove the address. Trust me, it’s better to be safe than sorry.


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About Melinda Plemel

Melinda has been working at Return Path for 9 years and is currently the Senior Industry Advocate and is responsible for managing global partners that join Return Path's Data Exchange program and emerging markets. She is the key to helping and educating Return Path on mailbox providers, anti-spam, and email technology trends, as well as to educating receivers about everything Return Path has to offer.

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