Would you rather have 10,000 people on your email list who ignore you? Or 1,000 subscribers who open, click, and buy?
As marketers, we can be a bit obsessed with big numbers. But a large database of disengaged contacts isn’t an asset. It’s a liability. It drags down deliverability, erodes trust, and makes every campaign harder to run.
As an experienced email marketing agency, we’ve seen both ends of the scale.
Prospects who’ve come to us after trying to buy their way to scale, but are now seeing campaigns failing. And small businesses that’ve strategically built and nurtured a smaller list of subscribers, turning them into reliable revenue streams.
When it comes to your email list, quality beats quantity every time.
In this blog, you’ll learn everything you need to know about building an email list for email marketing that delivers engagement and sales, and keeps you on the right side of ethical and legal considerations.
Why quality beats quantity in email list building
A smaller, engaged list consistently outperforms a large, unengaged one.
Although email marketing delivers returns as high as £42 for every £1 spent, this depends on the quality of your list.
Purchased lists can sink open rates to below 2% and many only contain around 30% valid addresses because providers don’t keep them clean.
Lack of performance like this doesn’t just hurt your ROI. It can end with your emails vanishing into spam folders.
As Seth Godin said when he described email marketing as “permission” marketing: “Permission Marketing is just like dating. It turns strangers into friends and friends into lifetime customers.”
Why buying and scraping emails can backfire
Buying or scraping email lists is short-term thinking that damages your reputation in the long run.
You’ll still hear marketers justify buying lists to get email marketing “moving quickly”.
But, while it can get you a list of emails to send content to, the reality is it’s not going to deliver good results. If anything, it’s going to make your brand known for spam emails that people don’t respond to.
Purchased lists are full of outdated or irrelevant addresses and often spam traps (an email address created and monitored by mailbox providers to identify and punish senders who send emails without permission, or don’t clean their lists).
It’s also pretty much impossible to personalise emails from a purchased list. You have no clue about the things those on the list like, or what type of content they’d be interested in.
Which is why most emails sent to a bought list are salesy, impersonal, and ineffective.
Send emails to a purchased list, and you could end up facing:
- Higher bounce rates and spam complaints
- Deliverability problems, including blacklisting
- Wasted spend on people who never opted in
What are the laws around email list building?
Privacy and compliance aren’t optional with email marketing. There are specific laws and legislation that you must comply with to send marketing emails.
In the UK, this is GDPR, which says:
- You need to get explicit consent before sending marketing emails
- That consent must be freely given, specific, informed, and unambiguous
- Recipients must be able to withdraw consent at any time
- Businesses must keep records of how consent was obtained
Fines for failing to comply with GDPR rules can be substantial, rising to up to £17.5m or 4% of global annual turnover in the most severe cases.
Even lower-tier breaches can leave you facing fines up to £8.7m or 2% of global annual turnover.
Look what happened to We Buy Any Car Limited in 2021.
The company was fined £200,000 by the UK Information Commissioner’s Office after sending more than 191 million unsolicited emails without valid consent, generating more than 7,700 complaints.
Proven ways to grow your email list
Customers have gotten smart to email marketing. Many don’t just hand over email addresses lightly anymore. Instead, they’re looking to get some value out of it. So you have to show the exchange is worth it for them.
There are a number of ways you can collect email addresses from customers:
These are forms on your website that ask for details. Keep them short. Just name and email can be enough to start with.
Most email signups happen on phones, so design pages and forms for mobile-first.
And test placement of forms. Test putting forms in the header and footer of your website, in the blog sidebar, within content, or set them as pop-ups as people scroll down or page, or when people try to click off a page.
For example, you could add a newsletter sign-up form to the bottom of your blog posts, or add an exit pop-up for a 15% discount on an eCommerce page.
Lead magnets
The key to lead magnets is they have to be valuable. Customers have become suspicious of lead magnets because too many companies use them as sales material disguised as valuable content to get contact details.
Marketers who use lead magnets report higher conversion rates than those who rely only on generic forms, according to one HubSpot study.
Formats like eBooks, guides, templates, swipe files, calculators and free tools all work well as lead magnets.
One bit of advice for lead magnets, make them specific to a challenge your prospects are trying to overcome that you can solve. A “B2B sales email template pack” will convert more than a generic marketing guide.
Content upgrades
This is similar to a lead magnet but is tied to the topic of a specific blog post.
For example, for a blog about technical SEO, you could offer a technical SEO checklist as a content upgrade to get an email address.
Like all lead magnets, you should make sure they’re valuable and specific to a problem.
Incentives
Discounts and free trials can work effectively when matched with user intent. For example, you could ask shoppers on an eCommerce website to subscribe to receive perks like early product access (like early access to a sale) or to receive member-only content, like exclusive offers and discounts.
Social proof
People are more likely to sign up for something if they know other people are already getting value from it. A good way to do this with email sign-ups is to highlight how many subscribers you already have, and what those people are getting.
For example: “Join 12,000 marketers who get weekly growth strategies” outperforms a simple “Subscribe.”
Webinars and events
Webinars are another form of lead magnet that’ve become more popular recently. But again, people who become suspicious that they’re just a sales pitch in disguise, so focus on making them valuable.
Walk-throughs, demos, how-to content and joint webinars with a customer often prove popular for getting emails.
They’re also ideal for combining with automated follow-up sequences to keep attendees engaged after the event.
Referral programmes
Make more use of the subscribers you’ve already got by giving them an incentive to invite people they know to your email list.
Offers like “refer a friend and you both get XYZ” work well for this.
Dropbox made good use of this tactic, growing its user base 60% through referrals.
And it can work just as well for membership and newsletter content.
You will need to track this carefully in your CRM or ESP, but if you’re organised, they’re easy to monitor.
Partnerships and co-marketing
If you have relationships with complementary brands or services, offer to collaborate and share audiences to grow both your email lists.
Events like joint webinars or content like joint guides or campaigns are mutually beneficial and give you both access to a bigger audience.
Collaborate with complementary brands to share audiences.
Offline opportunities
Email sign-ups aren’t just for online.
You can ask for sign-ups in-store, at events or at trade shows.
Simply use a QR code and set expectations that users are signing up for marketing emails to stay clear of GDPR issues.
How to nurture and engage subscribers (short- and long-term)
Building your list sets you up for success, but actual success comes from how you use that list to build a community and relationships with your audience. These are our top tips for nurturing and engaging your subscribers:
Early engagement:
- Send a welcome series. Your audience will never be more engaged than when they first sign up for your emails. Use a welcome series to deliver immediate value, set expectations for what someone gets for being on your list, and reinforce why subscribing was the right choice.
Long-term engagement:
- Segmentation: Segmenting your list is key to personalising email content and offers. Tailor smaller lists and content to interests, behaviours, or lifecycle stage.
- Content mix: Don’t just use your email list to send sales pitches. You’ll just get more people tuning out. But don’t forget the ultimate goal of an email list is to drive sales. Look for a balance between useful, interesting content with occasional promotions. Use your email data to find the right balance based on customer actions.
- Re-engagement campaigns: “Break up” emails or “we miss you” content can be useful for offering incentives for people to re-engage with your brand before you remove them from your list.
- List hygiene: Remove inactive or invalid emails. This improves deliverability and boosts engagement. For example, send a break-up email to anyone who hasn’t engaged with your content for six months and then remove anyone who doesn’t engage.
Read more about the 7 types of marketing emails every business should send.
The right email tools keep your marketing scalable and compliant. Look for:
- Consent tracking: Built-in GDPR features, audit trails
- Double opt-in: Verifies interest and prevents fake signups
- Segmentation tools: Behaviour- and interest-based targeting
- Analytics dashboards: Opens, clicks, conversions
Popular options:
- Mailchimp: Accessible for small businesses, strong automation
- HubSpot: Excellent for B2B, integrates CRM and content
- Klaviyo: Favoured in eCommerce for segmentation and predictive analytics
Build better email lists for long-term success
Effective email list building isn’t slower. It’s just smarter.
Marketers who can earn permissions to be in a customer’s inbox, by offering value to their audience, see more ROI, stronger deliverability and better brand reputation.
Those who look for shortcuts end up paying for any short-term uplift with complaints, fines and lost trust and brand reputation.
If you want help improving your results from email marketing, get in touch for a free strategy session.
If you’re just starting out, we can give you advice on how to begin with email marketing.
If you’re already sending emails but not seeing the results you want, our email experts and copywriters can help you figure out what kind of content your audience wants to
boost engagement and, in the end, boost sales.
Or you can read our complete guide to eCommerce email marketing to get more information.
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With six years of experience in SEO and Content Marketing, Kieran firmly has had a hand in both camps when it comes to this aspect of digital marketing.
Kieran started his marketing journey as a Content Executive, producing content for client websites. He then transitioned to the SEO department, as an SEO executive, applying technical SEO practices to better campaigns.
Kieran then moved to SEO manager, before transitioning into his new role of Head of Content Marketing, leading an exciting new era for the Content Marketing department!
Posted by: Kieran Ford
September 5, 2025