List hygiene

List hygiene is the practice of ‘cleaning out’ your contact base to remove unengaged and invalid recipients.

Your list hygiene has a direct impact on your deliverability as it affects the reputation of your sending IP and domain with mailbox providers.

A healthy sender reputation increases the likelihood of any email sent by your domain reaching a recipient’s main inbox, rather than their spam.

Invalid recipients

Invalid recipients are email addresses that don't exist and should not be in your subscriber list.

These can enter your list as a spelling mistake on sign-up, or because a contact has deliberately given a false address.

Unengaged recipients

Unengaged recipients are contacts that don’t open your emails and should be segmented and targeted differently from your engaged recipients.

See also: Email engagement bands in Ometria

Maintaining list hygiene

There are some simple changes you can make to your sign-up process which will prevent incorrect email addresses getting into your mailing lists:

1. Add reCaptcha to all sign-up avenues on your website. This prevents spam bots from adding email addresses to your list which can damage your reputation and lead to ‘listbombing’.

2. Implement a double opt-in process to stop disinterested contacts making it to your marketing list. Double opt-in also has positive results in engagement and conversion rates.

3. Ask your contacts to enter their email address into sign-up forms twice to reduce typing errors.

Competitions and list hygiene

Holding competitions can be a successful acquisition strategy when implemented correctly.

However, you can end up acquiring invalid email addresses and unengaged contacts, because visitors often sign up to competitions using a secondary or dormant email address, or sign up to a competition solely for the purpose of winning but will no longer engage with your emails afterwards.

Competition Spam Bot domains

There are a number of domains that are commonly associated with spam bots that attack competition forms on retailers' sites.  

Messages to these domains won’t be delivered and will artificially decrease your delivery and engagement metrics.

To prevent these email addresses from entering your list, implement reCAPTCHA on your competition and sign-up forms.

If you identify these addresses in your account, you will need to unsubscribe them from your subscriber base. In order to do this, you will need to search for the addresses using a segment, export the contacts and re-import them as an unsubscribed contact.

You can download this list as a .csv at the bottom of the page.

List hygiene and poor sender reputation

If poor reputation is the result of poor data collection and list hygiene, you can consider the following steps:

1. Remove addresses with typo domains. Typo domains account for the majority of invalid addresses and spam traps. Your Customer Success Representative can provide you with a list of common typo domains to help you create a suppression segment for this. You can then use this segment to force unsubscribe these contacts to permanently remove them from your contact lists. See also: How to segment out mistyped email domains
2. Invest in a list-validation service. This can be used to do one-off cleanses of your data to remove invalid addresses. These services can also be built into sign-up forms to prevent invalid addresses from being collected.