TOPIC
Social Proof in Email
Testimonials, expert endorsement, partnerships, awards, and user-generated content (UGC) build trust and credibility and ultimately lead to more sign-ups, more engagement, and more growth.
THEME
This campaign took inspiration from As Seen on TV infomercials, applying their persuasive tactics to email marketing, particularly through social proof.
The core idea stemmed from a LinkedIn post by an email expert who asked:
“If email were a pet, what kind would it be? And why?”
What Was Tested?
The goal was to validate whether a theme inspired by nostalgic late-night TV commercials and infomercial tactics would resonate with the audience, while also promoting the Ultimate Guide to Using Social Proof in Email and showcasing real social proof from the experiment as examples.
The campaign also included an A/B multivariate test:
50% of the audience received Subject Line A:
Ch-Ch-Ch-Chie Mail!
50% received Subject Line B:
Just Add Water
Both versions had the same preview text:
👀 Watch your inbox grow 🌱
Hypothesis
The assumption was that the Chia Pet reference would drive interest and increase open rates, based on strong engagement from the initial LinkedIn post. However, even while drafting the email, I was unsure about how well the Chia Pet analogy would translate into email growth.
Thus, I hypothesized that the subject line “Just Add Water”, paired with the preview “Watch your inbox grow”, would outperform the Chia Pet subject line due to its clearer alignment with the audience’s interest in email growth strategies.
Key Insights
Unexpected Apple Mail Behavior: iOS 18’s AI-generated preview displayed “Inbox growth expected.” This wasn’t present during testing, but it highlights the importance of ensuring that email content aligns with the subject line—especially for Apple Mail users.
Small Sample, High Engagement: The winning subject line was sent to any new subscribers who completed the welcome journey after the initial send. One recipient replied with an inquiry about the test, leading to direct engagement—a valuable outcome beyond just clicks.
OUTCOME
The test was conducted with 41 participants, and the results were clear:
✅ Winning Version: “Just Add Water”
- Open Rate: 65%
- Click Rate: 20%
❌ Losing Version: “Ch-Ch-Ch-Chie Mail!”
- Open Rate: 33.3%
- Click Rate: 9.5%
The winning subject line was sent to 5 additional participants::
- Open Rate: 60%
- Click Rate: 0%
(Metrics exclude Apple MPP)
Campaign Details
GOALS
- Educate: Demonstrate how social proof enhances email marketing using real subscriber-generated examples.
- Engage: Utilize infomercial-style storytelling, animation, video, and testimonials to captivate subscriber interest.
- Collect Data: Measure real-time engagement through an A/B multivariate subject line test.
Audience Size & Segmentation
- Initial A/B Test Send: 41 subscribers
(Completed Welcome Journey before Mon, Mar 3, 2025, 8:44 AM) - Resend to New Subscribers: 5 subscribers
(Completed Welcome Journey after Mon, Mar 3, 2025, 8:45 AM)
Test Methods
- Type of Test: A/B subject line test, referred to as Multivariate Test by Mailchimp.
- Audience Split: 50/50 between Subject Line A and Subject Line B in the initial test. The winning subject line combo was sent to new subscribers in the resend.
- Variations & Adjustments: The resend version included an intro message informing new subscribers they joined after the initial test and reinforcing they were receiving the winning subject line. The goal was to leverage high engagement levels from new subscribers who had just completed the welcome journey, making this their first newsletter.
Engagement KPIs
| Initial & Resend Combined excludes Apple MPP | Combined Total | Combined Rate |
|---|---|---|
| Sent | 46 | — |
| Delivered | 46 | 100.00% |
| Unique opens | 23 | 52.27% |
| Unique clicks | 6 | 13.64% |
| Clicks per unique opens | 6 | 26.09% |
| Bounces | 0 | 0.00% |
| Unsubscribes | 0 | 0.00% |
| Replies | 5 | 11.36% |
Mailchimp. powers this experiment. Information about Mailchimp’s Metrics can be viewed here.
Qualitative Feedback
💬 Direct Subscriber Comments:
- “Just saw the newsletter, how awesome!”
- “Brilliant newsletter, Danielle! Going to grab that resource later but so stoked with the way you tied that feedback in and illustrated social proof – Nice work 🙂“
- “Great email, as usual!”
💡 Long-Form Feedback:
“Of course, now the ONLY infomercial I can remember from the ‘good old days’ is the Chia Pet one. Bare Minerals and Proactiv also had some that were super effective, even without a catchy jingle. Honestly, I think they worked because they just wore you down by showing you their product in 25 different ways, over and over again, layering in social proof (of course) until you went from ‘I’m never buying that’ to ‘Take my money!’
Great analogy for email, because consistently showing up and reminding people of who you are and what you do is 80% of the battle, I think. 😂“
💭 Observations on Subscriber Interaction:
- Click engagement was lower than expected, but subscribers engaged via replies rather than clicks.
- The topic rating at the bottom of the email received no clicks, in contrast to the previous email.
📩 Recipient Inquiry:
“Curious to learn more about this test – it says it is a multivariate test. So what else did you change in both emails apart from the subject line?”
Questions, suggestions or takeaways to share? Email sender@tryandreply.email
Danielle Cambio
Marketing Technologist
Execute. Measure. Assess. Improve. Learn.
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