Is it worth sending emails to people who viewed a product but didn't opt-in?
Michael Ko
Co-founder & CEO, Suped
Published 25 May 2025
Updated 17 Aug 2025
6 min read
The question of whether to send emails to individuals who have viewed a product on your website but haven't explicitly opted into your mailing list is a common dilemma for marketers. On one hand, it feels like a missed opportunity to engage with potentially interested leads. On the other, it raises significant concerns about compliance, sender reputation, and brand perception.
My experience tells me that while the immediate urge might be to capitalize on every possible lead, acting without explicit consent can lead to more harm than good. This approach, often seen as aggressive or intrusive, risks alienating potential customers and can significantly damage your email program's long-term health.
The primary issues revolve around legal compliance, maintaining a strong sender reputation, and preserving your brand's integrity. These factors are interdependent, and a misstep in one area can quickly cascade into problems across your entire email marketing strategy.
Understanding email consent laws
Navigating the legal landscape of email marketing is crucial, and consent is at its core. Laws like GDPR in Europe, CAN-SPAM in the United States, and CASL in Canada all dictate strict rules around who you can email and under what circumstances. Generally, these laws require explicit permission before sending marketing communications.
While some regions allow for a 'soft opt-in' where an existing business relationship might permit certain transactional or marketing emails, relying on product viewership alone for unsolicited marketing emails is highly risky. It's often not considered sufficient consent under most regulations, especially for new contacts. Understanding these regulations is vital for your email program, and it impacts everything from list acquisition to your sending frequency. You can find more details on general email laws and regulations in this guide from Campaign Monitor on email laws.
If someone viewed a product but didn't sign up for your newsletter or create an account, they haven't given you explicit permission to market to them. Sending an email in this scenario could be seen as unsolicited commercial email (spam), leading to legal penalties and fines. It's also important to consider if opt-in buttons should be checked by default on your forms, as pre-checked boxes often do not constitute valid consent under strict regulations like GDPR.
Best practice for consent
Explicit consent: Always obtain clear, unambiguous consent before sending marketing emails. This means a user actively agrees to receive your communications, such as by ticking an unchecked box or submitting a form specifically for newsletter sign-ups. More information on soft opt-ins can be found at dpnetwork.org.uk.
Transparency: Clearly state what kind of emails subscribers will receive.
Easy unsubscribe: Provide a clear and easy way for recipients to opt out of future emails.
Always prioritize the legal requirements of the regions where your recipients are located. Non-compliance can lead to severe fines and a damaged reputation, far outweighing any potential short-term sales gains from sending to non-opted-in users.
Why unsolicited emails hurt your deliverability
Beyond legal implications, sending emails to people who haven't opted in poses a significant threat to your sender reputation and overall email deliverability. Internet Service Providers (ISPs) like Gmail and Yahoo (among others) closely monitor how recipients interact with your emails. A high number of spam complaints, low open rates, and increased unsubscribes signal to ISPs that your emails are unwelcome.
When ISPs detect these negative engagement metrics, they can start routing your emails directly to the spam folder, or even block (blacklist) them entirely. Once your IP address or domain gets on a blacklist or blocklist, it becomes incredibly difficult to reach anyone's inbox, even for your legitimate, opted-in subscribers. This is a common factor in why your emails go to spam.
Permission-based sending
Higher engagement: Recipients are genuinely interested, leading to better open and click rates.
Improved deliverability: Lower spam complaints and higher sender reputation (or domain reputation) mean more emails reach the inbox.
Reduced blocklisting risk: Less likely to trigger spam traps or be reported as spam.
Unsolicited sending
Low engagement: Recipients are not expecting your email, leading to low opens and clicks.
Damaged deliverability: High spam complaints and unsubscribes hurt your sender reputation, leading to filtering.
Increased blocklisting risk: Greater chance of being placed on a blocklist (or blacklist) due to negative feedback.
Ultimately, sending to product viewers who haven't opted in is a direct path to the spam folder, diminishing your overall email marketing effectiveness. It's often categorized as a key risk of sending email to inactive users, even if their inactivity is only related to lack of explicit consent.
The long-term cost of short-term gains
My biggest concern with sending emails to non-opted-in product viewers, especially with discount offers, is the potential for significant brand damage. While it might seem like a quick win for sales, this tactic can cheapen your brand experience and erode customer trust over time.
Imagine a potential customer browsing your site. They view a few products, then suddenly receive an unsolicited email offering a discount on one of those items. This can feel intrusive, like they are being followed around the shop, as some might put it. It shifts the perception of your brand from one that values relationship-building to one that simply barrages users with sales pitches.
Customers who feel harassed or spammed are unlikely to become loyal advocates. Instead, they might develop a negative association with your brand, making them less likely to engage with future, legitimate marketing efforts. This includes re-engaging inactive subscribers a challenge if initial impressions are poor. The goal should always be to build trust and a positive user experience, which permission-based marketing excels at.
Views from the trenches
Best practices
Always prioritize explicit consent for marketing emails, it builds trust and improves engagement.
Segment your audience based on consent status, ensuring you only mail opted-in users for marketing.
Implement double opt-in for new subscribers to confirm their willingness to receive your emails.
Focus on delivering value and building relationships rather than solely pushing discount offers.
Regularly clean your email lists to remove inactive or disengaged subscribers.
Common pitfalls
Sending emails to users who haven't explicitly opted in, even if they've viewed products.
Ignoring email deliverability metrics like spam complaints and bounce rates.
Over-relying on discount-driven emails without building brand value.
Not providing a clear and easy unsubscribe option in every email.
Purchasing or using third-party email lists without verified consent.
Expert tips
For abandoned cart emails, ensure users have provided at least an implicit consent through the checkout process.
Personalize emails based on browsing behavior only for opted-in segments.
Use transactional emails (like order confirmations) to subtly encourage marketing opt-ins.
Monitor your sender reputation using tools like Google Postmaster Tools.
Test different consent acquisition methods to see what works best for your audience.
Expert view
Expert from Email Geeks says that deliverability concerns are paramount, especially regarding spam reports if recipients haven't explicitly opted in.
2023-10-18 - Email Geeks
Marketer view
Marketer from Email Geeks says that whether recipients are opted-in for commercial marketing emails is the crucial question when considering sending to product viewers.
2023-10-18 - Email Geeks
Making informed decisions for email marketing
In my opinion, the answer to whether it's worth sending emails to people who viewed a product but didn't opt-in is generally no, especially for marketing communications. While the allure of potential sales is strong, the risks to your email deliverability, sender reputation, and brand equity are substantial and often irreversible.
Instead of chasing every potential lead with unsolicited emails, I advise focusing on building a robust, permission-based email list. This means encouraging explicit opt-ins through valuable content, clear sign-up forms, and transparent communication about your email practices. For existing customers, ensure you adhere to legal and advisable terms of service emails while still respecting their unsubscribe status for marketing.
By prioritizing consent and a positive recipient experience, you not only comply with regulations but also cultivate a more engaged and loyal subscriber base. This foundation is essential for long-term email marketing success and avoiding common pitfalls like low open rates even with high inboxing. Focus on quality over quantity for sustainable growth.
Gmail and 
Yahoo (among others) closely monitor how recipients interact with your emails. A high number of spam complaints, low open rates, and increased unsubscribes signal to ISPs that your emails are unwelcome.
