How I got 10.000 emails for launching our newsletter | Datasketch
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How I got 10.000 emails for launching our newsletter

Tips and tricks to grow your email list from people you already know. Datapreneur.

I have been waiting for this moment for a long time. I started Datasketch in 2015, providing data science services on my own, slowly growing the team as more projects came, and trying continuously to buy time bootstrapping to create a product to democratize data science for non-techies. The product finally is in good shape, not perfect but getting better and better, so now we are starting some marketing efforts.

If you are getting bored with our story, head over to the list of tips

We are not launching a newsletter; we are actually launching four newsletters. That’s because segmentation has been an issue for us for a couple of years. We work at the intersection of different communities with something in common: Big Small Data (more on that in another post). The challenge with that is that the language and the relevant stories for the communities do not really overlap. We came to see that when we raised $60k in a Kickstarter campaign a year and a half ago. It was really challenging to talk to that small intersection of communities of people interested in open source, data science, data journalism, and civic-tech was not easy at all. We came to realize that those more tech-oriented are not necessarily interested in public issues. Those interested in innovation for decision-making are not necessarily aware or interested in open source or data science. Those interested in social problems or democracy are not necessarily aware of data journalism and civic-tech and how it could be beneficial. So far, our best-informed guess is to segment our users in for buckets: Open government, Data journalism, Data Culture, and Entrepreneurship with data, and thus we are launching these newsletters.

If you have read this far, you are probably interested in our Datapreneur newsletter, so now it would be an excellent time to sign up and get more tips on leveraging data for your startup or project

What we will cover in this post:

  • Where do I start to get initial emails for launching my project
  • That’s crazy! How you can know 10.000 people personally
  • Contacts you already have in front of you
    • Your current email provide contacts
    • Your old emails
    • Sync contacts
    • Email lists
    • Scrape emails
    • Your Linkedin contacts
    • Your Twitter contacts and Facebook contacts
    • Your Whatsapp contacts and groups
    • Run surveys
    • Your calendar invites
    • Events and conferences
    • More tips: Zoom, reply-all, etc.
  • How to expand your email sources to get even more emails
  • Cleaning up your email lists
    • What their first name and last name?
    • Manual data cleaning tools
  • Enriching the data in your email lists
    • What language do they speak?
    • Where do they live?
  • Segmenting your lists
    • What are they interested in?
    • What are their interests?
    • Set, ready, launch!
  • Measure and learn
  • Tracking people attributes and low-code set up to send personalized messages
  • Going beyond email: text and Whatsapp

Where do I start to get initial emails for launching my project

If you are somewhat interested in social science, you have probably heard of Dunbar’s Number, we can start there. People usually have 150 friends with whom they build meaningful relationships. If you are starting a newsletter, those 150 are a good starting point, but you can do better. You can include acquaintances of all sorts.

How many acquaintances do people have?

There are many ways to estimate personal network worth, suggested Tyler McCormick and friends. Unsurprisingly (perhaps to some data scientists, but we are not all data scientists), the distribution resembles a Power Law. This means: many people have few friends, and few have many friends (in reality, it resembles more a log-normal distribution).

Formula for calculating personal network

NOTE: If you want to learn more about Power Laws, check out this TED Video: The surprising math of cities and corporations

According to the paper, the median network size of a person is 472, and the mean network size is 611 people. Interesting note: the researchers found that males have a slightly higher number of connections, where 90% of males have between 172 and 1581 connections. For females, it was between 157 and 1488.

That’s crazy! How you can know 10.000 people personally

The answer is I don’t. Instead, I have simply been methodical in collecting emails from people we know (my colleagues and I) at every opportunity, whether at a conference, on a trip, online surveys we have done, and more.

By organizing all this information from multiple sources: social media, messaging groups, forums, business cards. Even with a low online presence, I am sure anyone can start implementing the recommendations in this post and get a couple thousand emails. Ping me on Twitter if you try it, I’d love to see if my guesstimate is correct.

You will email all those people, and they won’t remember you

Correct, most people won’t even know how I got their emails. But that’s ok (I hope); I’ll send a reminder long with my picture saying hi.

If you know how to code, that’s probably easy for you but not for me

I do code, but the tips I am presenting here were actually done using manual work or no-code tools. Start with a spreadsheet, and you are good to go.

If I don’t know anyone, how do I get their emails?

Simply ask for them. Sounds stupid and straightforward, but that’s how it is. If you are building something, asking people for help is very valuable. You can reach out to people via texts, forums, or even asking random people in the streets. Just make sure you organize the information you collect in a spreadsheet.

Here are a couple ways to collect 10.000 emails.

  • Participate in a webinar, drop your email and ask others to do the same. You could perhaps get up to 10 emails at each call/webinar.
  • Organize your contact information from multiple email providers. You can quickly get to 1000 or more emails (you’ll get irrelevant email addresses like sales or, but you can get rid of those later)
  • Ask your Facebook, Linkedin, or Twitter friends for their email via direct message. Very practical, it would take maybe a day to ask 100 hundred people for their email addresses.
  • Keep all business cards you get and save their contact info to a spreadsheet.
  • Scrape your contacts from multiple email accounts. Important! See below for details.

Contacts you already have in front of you

Let’s dive deep into the different channels you can use to get emails from people you already know.

Ensure you organize all the contact files you download in a single repository, folder, or cloud drive. Make sure to name the files with explicit names. It could help to keep also a date on the downloaded file name. So you can track later where and when you know the person from. Let’s start.

Your current email provider contacts

You may regularly use one, two, or even three email accounts. Make sure you go to the contacts page and export all your contact data as a CSV file. For example, in Gmail, you can go to; if you are using Yahoo, you can go to; I guess every email provider has the option to export contacts.

With this strategy, you could get between a couple hundred and a couple thousand contacts

Your old emails

Make sure you do the same for those old email addresses. You’ll probably get a blast remembering those teenage email accounts from your friends

With this strategy, you could get a couple hundred emails

Sync emails

There are a few ways to sync contacts from multiple accounts, including social media.

  • Contact+, formerly FullContact, provides a great way to keep contacts in sync. Some of the handy options like reviewing duplicates maybe be accessible only via subscription.
  • Different mail clients also allow syncing data and contacts from multiple email accounts. For example, I used Thunderbird to keep a local copy of all my emails that I could later use to collect emails from people in my inbox. (see bellow: scraping emails).
  • Other options include Contacts in macOS and Kontact for Linux.

Any of those tools should work; make sure first you can export your contact information as a spreadsheet or CSV. Other features like merging duplicates are helpful but more necessary down the line when you have enough emails to process.

With this strategy, you could get a couple thousand emails

Email lists or groups

You are probably subscribed to multiple email lists that you find interesting. This is really important because others subscribe to the same list, and they share the same interests.

If you don’t remember which lists you are subscribed to, go to your email now and hit the search bar with “list.”

You will probably find many emails there; make sure you search for email lists where people can reply, like google groups. You can start taking note of who writes where and what they are interested in; this is important for you to later reach out with relevant information.

With this strategy, you can get a hundred thousand emails depending on the lists: how many, how big, and how active they are

If you are not subscribed to any email groups or lists, make sure you join some now. Search for groups that are of interest to you. If you don’t know where to start, you can search first on


Scrape emails from your inbox… Important step!

After identifying those newsletters and email lists relevant to you or your audience, start taking note of who may be interested in the type of content you are producing.

If you do this manually, that’s perfectly fine, that’s how I did it initially, but it got to a point where I could really use some automated way to collect all those emails… enter scraping your own email

If you code, you can get a dump of your email and run a regex on all texts.


If you are not a coder or a lazy coder who many times prefer point and click tools - like me, keep reading

Make sure you get a dump of your email account. The way I did, it was by installing Thunderbird and set it up as my email client on my desktop (works on Windows, macOS, and Linux). It works with multiple accounts. So now you have a quick way to have all your emails in a single place.


You can use it to read and send emails from your desktop, and guess what, it comes with some add ons you can install for specific tasks. I synced multiple contacts and managed to scrape emails from my own email using the Email address crawler

pasted-image pasted-image

I faced some issues installing the Add On on Linux. Expect some googling to make it work. I had to install a previous version, but that was a while ago; perhaps it works better now.

That’s how I could scrape emails from my own inbox; the best thing is that you can crawl for emails in specific folders.

It is crucial to send relevant emails to your audience. Try to organize emails in folders so you can message people according to their interests. This is how I did it:

  • In my web email client, I set up some custom filters with specific keywords, say “transparency” or “journalism,” to search my inbox.
  • Added labels to those emails; those labels inside Thunderbird are synced as folders.
  • Use crawlers specifically for each folder with the relevant labels for your audience.

That’s it, go ahead and collect another couple thousand emails.

Your Linkedin contacts

I collected information on my Linkedin contacts using Contacts+, but that was a long time ago. Recently I found out about SaleQL. It seems to work pretty well, so next time I need to sync emails from Linkedin contacts, I will probably use it. For free, you get 100 emails; for $39, you can get 1.500 emails from people you already know.


How about Linkedin polls? I heard they work well for more outreach, not sure if you can get their emails directly, but you can friend them and use the tip above. If you have any other ideas about getting emails from Linkedin, ping me on Twitter.

Your Twitter and Facebook contacts

I don’t know of another way than using direct messages to ask your friends for their email. It may not be scalable, but you are actually getting their permission to email them with this direct approach, so that’s nice.

Another way is to post any type of research (with an email field) that you post on Twitter or Facebook. Then, run small surveys and questionnaires by linking to google forms or Typeform, my favorite survey tool.

Your Whatsapp contacts and groups

Your Whatsapp contacts and groups

** Note: Most of the tips in this section also work for Slack or Telegram**

Again, just try to send a direct message and see how it goes. You can send a message like this:


This is just some random guy from India; it amazes me how awesome people are if you simply ask for help. Note that you can send direct messages to anyone in the groups you belong to, so there is no need to actually have those contacts in the address book. If you belong to a couple groups, that’s already a few hundred contacts there.

You can also search within the groups for common email domains to get hits like this:


Did you know you can export your Whatsapp group chats to a text file?. Go to your group > Options >More > Export chat > Export without media (no need to save cat pictures).

Then within your texts, you can search for @ symbols or use our Data App to extract emails from texts.


When you export your chat texts, it also exports all the contacts that have been shared to a group.

This is my contact information being shared in a group of 100+ people. pasted-image

Recommendation: whenever you want to share a contact, do it via direct message and get permission before.

Run surveys, questionnaires, and forms

I haven’t had a Facebook account in years. When I left, I posted a survey for people to keep in touch. If I recall right, at least 5% of my Facebook friends left their email. So surveys and questionnaires in social media work.

We have mapped out every single survey we have made and organized the emails from those. Here are some ideas on surveys, questionnaires, or forms that you may have run but don’t remember:

  • Job application forms
  • Attendees to any event or reception you have hosted
  • Feedback from potential users
  • Customer satisfaction surveys
  • … any more ideas? post them on Twitter

Go ahead and log into your accounts at Typeform, SurveyMonkey, Wuffoo and see if you did any survey in the past and reconnect with those contacts via email.

We personally have done this with google forms many times. Some may not know that you can convert your google form responses to a spreadsheet. Log into your google drive and start searching for terms like email, attendees, registration, confirmation and download all those email lists from your drive.

Your calendar invites

Go to your calendar and export it. In Outlook, you can simply click File > Open & Export. In Google Calendar, go to Settings > Import & export.

You will end up with a .ics file. If you open the file in a text editor, you will see calendar event details with title, description, date and time, location, etc.

If you have a decent number of meetings per week and have a history of a couple of years with your email account, you could get hundreds and even low thousands of emails this way.

The easiest way to parse those .ics files to get a spreadsheet is by uploading it to our Parse Calendar Data App


If you can code, here are a couple of libraries you can use to read and structure your calendar .ics data.

More tips

  • Zooms: Some people wave goodbye and leave their contact info. Since last year the amount of group calls we all participate in has grown considerably. Take any chance to ask for an email.
  • The “reply all” people: Sometimes people simply hit reply all unnecessarily. This can be annoying and an opportunity to identify those people, along with their emails, interested in a specific topic. Make sure to save those emails, tag them with a label or add them to a folder in your email client so you can find them easily later.
  • Events and conferences: Before COVID, I traveled too much, tired of attending different events. No matter how tired I was, every day after the conference, I came back and noted the names and email addresses of speakers and fellow attendees I met. Even at workshop tables, I would sometimes take out a piece of paper and ask people to write down their emails to keep in touch with me and receive content about [insert conference topic here].

Now that you have collected all those emails. What’s next?.

Having all those emails collected doesn’t really help if you don’t provide them with valuable content. The main challenge now is how do I organize all those emails to make sense for my business?

Some risks now involve:

  • Sending duplicate emails
  • Not referring to people by their first name properly
  • Making sure the content you send them is relevant

I actually lied a little bit at the beginning of the post. I did not collet 10.000 emails; it was more than 15.000 emails. Sending the wrong email to the right people is something that you may not afford.

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This post ended up being longer than I thought. In the next post, I will tell you about the data cleaning process and enriching the data you have collected to put it to good use.

  • Cleaning up your email lists
    • What their first name and last name?
    • Manual data cleaning tools
  • Enriching the data in your email lists
    • What language do they speak?
    • Where do they live?
  • Segmenting your lists
    • What are they interested in?
    • What are their interests?
    • Set, ready, launch!

Some other upcoming blogposts for later blog posts:

  • Measure and learn
  • Tracking people attributes and low-code set up to send personalized messages
  • Going beyond email: text and Whatsapp

Stay tuned.