Act! Blog

An overview of best practices for inbox placement

One of the critical aspects of an effective email marketing strategy is maximizing email deliverability and inbox placement. Recipient inbox providers and email filtering services track your email sending history and use algorithms to measure your sender reputation – in other words, they gauge how likely you are to send high quality emails based on your past behavior, and use this estimate to help determine whether your next email will be rejected, sent to junk/spam, or delivered to the inbox.

Importance of sender reputation

A good reputation results in higher inbox placement and more opportunities for conversion. A bad reputation produces not only lower conversion rates, but could result in all of your emails being blocked. Your sender reputation holds you accountable to your recipients, their inbox provider, and any other entities that facilitate the delivery of your email.

Managing your sender reputation is as simple as following best practices for the three areas that impact your email quality:

  • how you generate leads
  • how you send email
  • how you maintain your email marketing list

Keep in mind that sender reputation is a holistic measurement so it’s important to commit to all of these practices to optimize results.

Best practices for lead generation

Explicit permission – The number one rule

Only send marketing email to recipients that have provided explicit permission for you to do so. The permission must be freely given, specific, informed and unambiguous. Try to always use an electronic form to keep record of the consent even when subscribers make the request for marketing in person.

  • Freely given – Truly voluntary. Denial or withdrawal of permission must not imply negative consequences for the subscriber.
  • Specific – Subscribers should know the specific purpose for which they are providing their email address, and if there is more than one purpose, there should be separate consent for each.
  • Informed – Details of the permission must be clear and distinct from other text, not buried inside a paragraph or terms of service.
  • Unambiguous – Permission must be indicated through an affirmative act or declaration, preferably a checkbox that is defaulted to un-ticked. A pre-ticked box or lack of objection (e.g. “they didn’t say they didn’t want marketing…”) does not constitute permission.

Collecting email addresses from an association, affiliates, joint venture partner, or purchasing addresses through a list provider is not considered a source of opt-in. Use of these types of sources is a fundamentally poor practice because there is no opportunity for the recipient to provide explicit permission.

Email confirmation (AKA double opt-in)

As an extension of permission, confirm each subscriber’s identity and intent to receive marketing on the first email you send them by asking them to click a link or take some other affirmative act. This ensures that the person that filled out the form is actually responsible for the email address they provided.

Setting expectations

Set clear and specific expectations at the time of opt-in for the subscriber about your emails:

  • What will the emails be about?
  • When and how often will you send them?
  • Who will they come from? (Your sending domain, branding, logos, colors, etc.)

Best practices for sending email

Meeting expectations

Consistently deliver mail that meets the subscriber’s expectations for content, frequency and identity that you set when you obtained permission. If any of this is going to change (e.g. branding or logo update) be sure to let your subscribers know. If the changes are significant, reacquire permission and set new expectations at that time.


Segment your lists according to differences in content, frequency, and identity so that subscribers only receive what they requested. This also allows you to cater to subscribers with different interest levels or email preferences.

Subject lines

Describe plainly and clearly what you are sending. Subject lines that contain spam-like keywords, or are misleading or vague will likely get flagged as spam.


Ask your subscribers to add your sending address to their contacts or safe sender list.


Make it easy to unsubscribe. When subscribers find it hard or impossible to unsubscribe, they often mark the email as spam. A single unsubscribe is better than a single spam compliant, any day!

Legal awareness

Be aware of and comply with email related laws that apply to you AND to your subscribers (e.g. CAN-SPAM, CASL, GDPR, etc.). Remember that sending email is often international and you’ll need to respect the laws of the destination as well as the origin. Legal consequences aside, non-compliant emails are a red flag for spam filters and recipient inbox providers.

Objectionable content

Avoid objectionable content, even if your subscribers have agreed to view it. Spam filters will often pick up on objectionable keywords, regardless of your relationship with the recipient.

Best practices for list maintenance

Regularly remove the following high risk subscribers from your marketing list:

Unengaged subscribers

As a general rule, these are subscribers that have not opened or clicked in the past 6 months though this depends on how often you send. For example, if you send daily emails, a subscriber could be considered unengaged if they don’t have any activity after one only month. Attempt to re-engage with these subscribers early by offering a special promotion or incentive to show signs of interest, don’t wait until they become too much of a risk to send them marketing.

Role accounts

Email addresses that consist of a role instead of a name, like info@, admin@, or sales@. Role accounts are often shared or passed down as people change roles at a company, which means you could be sending marketing to someone without permission.

Lost or forgotten subscribers

Permission degrades over periods of inactivity. Don’t send to an old list of subscribers if you haven’t been emailing them within the past 6 months, even if you obtained explicit permission at the beginning of your relationship.

The hard truth

Many senders struggle with letting go of these “leads”.  Don’t be tempted to hang on to unengaged or other high risk recipients. This only hurts your inbox placement with prospects that have the highest potential for conversion: your active and engaged subscribers.

The best email is both wanted and expected

How you generate leads, how you send email, and how you maintain your email marketing list all impact your sender reputation and inbox placement. Be sure to commit to best practices in each of these categories to maintain an excellent reputation. If you feel unsure about how to implement a particular practice, let transparency be your guide. Be clear about your intentions and consistently meet your subscribers’ expectations.

At the end of the day, your goal is to make sure every email is both wanted and expected by your subscribers. With this approach, you’ll develop trust with both your subscribers and their inbox providers – trust that will benefit your business far beyond just email deliverability.