How to filter bot activity in emails with Marketo

First, it’s important to clarify that this feature only detects bots that interact with your emails.

To fully understand this functionality, let’s answer two key questions:

What does it do?

• It manages “email open” and “click link” activities in the activity log that could be triggered by bots.

Why did Marketo introduce this feature?

Adobe launched this feature in 2021. According to one of its Product Managers, it was developed to “address the impact of bots on email engagement.”

During the initial release, Marketo’s bot filtering captured an average of 2 million bot activities per week across 1,000 customer accounts. This represented about 3% of all recorded email clicks and opens, significantly lower than the industry average of 15% to 30%.

If you don’t filter bots, you could be making decisions based on false engagement data. Here are four real-world consequences of failing to detect bot activity:

1. Leads with inflated scoring

Marketo’s Lead Scoring system assigns points based on user activity. If bots generate fake clicks and opens, certain leads will appear more engaged than they actually are.

2. Distorted reports and inaccurate A/B testing

If your engagement data is unreliable, so are your reports—and by extension, your strategic decisions. Imagine running an A/B test where Email A wins. Now, imagine that 15% of the clicks on Email A were generated by bots. You’d be making decisions based on false data.

3. Automated workflows triggered by fake clicks

Bots can click on an email and trigger automated workflows, leading to unnecessary follow-up emails or even moving leads into later stages of your sales funnel when no human interaction has actually taken place.

4. Wasted human and technological resources

In the worst cases, sales teams could waste time contacting “engaged” leads that actually haven’t interacted with your content at all.

Now that we understand the context and consequences, let’s explore how Marketo actually filters bot activities.

Marketo uses two primary methods to detect bot activity in email campaigns:

1. Matching Against the IAB Bot List

Marketo compares email opens and clicks with a bot list maintained by the Interactive Advertising Bureau (IAB).

What is the IAB bot list?

The IAB (Interactive Advertising Bureau) is an organization that sets standards for digital advertising to improve campaign effectiveness and prevent fraud.

Their bot list identifies email accounts used by bots that open emails and click links automatically. This allows companies to filter out fake interactions and gain more accurate engagement data in email marketing campaigns.

2. Proximity Pattern Matching

If a single lead performs multiple activities within X seconds, it is flagged as bot activity.

You can adjust this threshold up to 3 seconds to improve detection accuracy.

Example:

If a lead opens an email and clicks a link within the same second, Marketo will classify this as bot activity.

Enabling this feature is simple. Follow these steps:

1. Go to the Admin module in Marketo.

2. Select Email → Bot Activity.

3. Enable bot detection using one or both options:

• • IAB bot list filtering

1. • Proximity pattern detection

4. Choose how to handle bot activity for each detection method:

• Log bot activity: This records bot activity in the activity log, allowing you to analyze it. You’ll also get new constraints in the “open” and “click link” activities to filter these interactions in smart lists.
• Filter bot activity: This completely removes bot-generated activity from Marketo, preventing it from being recorded at all.

5. Adjust the proximity detection threshold (starting with 3 seconds is recommended, then refine as needed).

6. Save your changes and monitor the impact on your metrics.

1. Proximity Detection Timing

• 0 seconds: Any repeated activity within the same second is flagged as bot activity.
• Up to 3 seconds: Any repeated activity within the configured timeframe is flagged as bot activity.

2. Impact on Engagement Metrics

• If you choose “Filter bot activity”, your open and click rates may decrease.
• This is actually a good sign—it means your reports are now reflecting real human interactions.

3. Using Smart Lists for Bot Analysis

• You can use the filters “Is Bot Activity” (Yes/No) and “Bot Activity Pattern” in smart lists to analyze trends.
• These filters can be applied to “Clicked Link in Email” and “Opened Email” activities for more precise segmentation.

4. IP Validation Before Blocking

Marketo manually reviews each IP before adding it to the bot list, ensuring that only critical and harmful addresses are blocked.

If you’re using Marketo and haven’t activated bot detection, your engagement data may already be distorted without you realizing it.

Enabling Bot Activity Filtering ensures that your lead scoring is accurate, prevents unnecessary automation triggers, and guarantees that your reports reflect genuine interactions.

Take action now. Enable this feature in your Marketo account, monitor its impact, and adjust the settings to find the right balance between accuracy and effectiveness.