List Hygiene – Keeping Your Subscriber Database Current and Relevant


    What is List Hygiene?

    List hygiene is a best-practice technique of keeping your subscriber database free of inactive and unresponsive subscribers by amending, unsubscribing, deactivating, or removing their contact details from your database.

    What’s in it for you?

    Some ISPs use expired email addresses as ‘spam traps’ as a monitoring tool; that is, they treat any email sent to these email addresses as ‘spam’.

    Spam traps, ‘unknown user’ bounces, and blacklistings (along with other metrics) all contribute towards your sender reputation with ISPs. Sending too many emails to bad, cancelled, expired or invalid email addresses can make you look spammy and could lead to your communications being blocked and/or blacklisted by one or more ISPs. Getting blocked or blacklisted by one ISP can lead to a knock-on effect with others, resulting in a poor sending reputation. Gaining a poor sending reputation is counter-productive to any communication campaign.

    What can you do to get started?

    Here are a few pointers that will help you get started:

    Prevention is always best

    You can minimize your exposure to invalid email addresses by implementing confirmed/double opt-in mechanisms (and data checkers for email address format) on your website. Having this form of sign-up mechanism can help catch mis-typed details (notably email addresses) and may even help you avoid spam-traps and other non-responding email addresses being added into your database.

    Give subscribers the power to choose

    By asking a few well-thought-out questions at the sign up stage, you give your subscribers the opportunity of choosing what kind of content they would like to receive from you and also how often. Make sure you respect their choices when you send them communications.

    Avoid poor database sources

    Harvesting contact details from websites, acquiring databases from third parties, or even collecting contact details at point-of-sale without informing customers of the purpose of gathering their information can lead to high numbers of complaints and/or unsubscribes. Remember that in most cases you must have express consent to communicate with your subscriber database members.

    Avoid role-based email addresses

    Email addresses such as ‘info@’, ‘sales@’ and so on are easily accessible from websites and are therefore generally prime targets for spammers. Add to this the fact that email addresses of this nature are generally monitored by more than one person; you could lose your intended audience simply because you didn’t take the time to gather personal contact information. Think about whether you want to be communicating with any abuse@ or spam@ email address.

    Consider how you communicate

    A targeted communication is generally more effective than a ‘blast’. If you’ve already asked questions of your subscribers as to what type of information they’re interested in receiving from you and how often, then target your communications based on your subscribers’ answers. Gathering information about your subscribers will enable you to target your communications effectively, resulting in your subscribers receiving what may be of interest to them and keeping them engaged and less likely to be a non-opener.

    Review your database regularly

    How regularly you perform this review depends on the volume and frequency of your communications. Review bouncebacks and dis-engaged subscribers. Amend email addresses that have obvious typing errors (e.g. instead of, deactivate email addresses that have bounced but don’t have an obvious typing error.

    Consider a re-engagement strategy

    When reviewing your dis-engaged subscribers consider whether you are able to re-engage them in some way. If not, then deactivate their record in your database.

    What does gCastTM do to help you?

    gCast has a number of features that can assist you with list hygiene practices:

    An automated unsubscribe mechanism

    When a subscriber clicks on the ‘unsubscribe’ link in an email sent via gCast they will be unsubscribed in minutes or will receive an email asking them to confirm their intention to unsubscribe (depending on your preferences).

    Effective handling of hard bouncebacks

    Most hard bouncebacks are handled automatically with gCast marking those email addresses as bad where applicable and ensuring they will not be included in future gCast communications.

    Duplicate record detection

    Not only can gCast recognize duplicate records at the import stage, giving you an opportunity to address the issue prior to import but it also allows you to handle any potential duplicate records that may already exist in your gCast subscriber database. Additionally, gCast users have the ability to toggle campaigns to only send one email where subscribers appear to be sharing an email address.

    Data checking

    The gCast data import process performs syntactical data checking and will, where logical and appropriate fix up issues on import. Additionally, gCast holds its own dynamic database of invalid email domains (based on DNS lookups) and scans this prior to each send from the platform, preventing any matches from being sent at all and eventually marking as bad any email address that displays repeated attempts at sending.

    Feedback loops

    gCast subscribes to feedback loops with major ISPs. Feedback loop notifications are processed on receipt and the subscriber is unsubscribed in minutes.

    Share your tips and ideas

    We’d love to hear your feedback and comments on this topic, do you have any success stories, or maybe some additional hints and tips you’d like to share? Submit your comments!

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