I obtained almost 3,000 email addresses in under 24 hours by posting a single thread on Reddit

Long story short, I did the "get my e-book free for the next 24 hours" tactic to farm email addresses and used Gumroad.com as the platform for people to download (I don't have a landing page yet, working on that)

I posted the promo on a Subreddit related to my target audience. People liked it, a lot. It's currently the highest rated post of the week on the subreddit I posted in. Gumroad requires an email address from all people who download my products and conveniently complies them in a nice list.

I'm a complete noob to email list building, but did I do it right? (Honest question)

I thought it'd take months and months to obtain just 1,000 email addresses. But I got almost TRIPLE that amount in LESS THAN 24 hours by posting a single, intuitive post on Reddit that provided lengthy valuable information and at the very end, a link to download my ebook for free.

You can't just make a spammy "Hey, download my free ebook" post with no other information or help (Redditors despise that, so you have to disguise anything you promote on Reddit in a way that doesn't seem like you're just using them for your own benefit. Provide incentive and credibility)

Is this a reliable method of obtaining emails? Furthermore, every email is from people in my targeted audience, who are interested in my e-book (more of an e-commerce guide), not just random people, so that's got to be even more valuable.

Gumroad even allows you to send mass emails to all of your customers internally on the site. I'll plan to market my other guides to the people I racked up on reddit sometime in the near future, don't want to seem desperate and send promo emails right away, would waiting be the right tactic? Or do you guys just move right in for the kill?

Should I continue to use Gumroad to acquire emails? Its super user-friendly. Not a single complaint from anyone who downloaded it

Also, what is even a "good" amount of email addresses one needs to be considered decent sized and worthwhile? Is 3,000 enough? Hardly enough? More than enough?

I'm honestly not sure if I just got extremely lucky, or if it's really that simple to get emails. Never would have thought, otherwise I would have done this months ago. But now I know.

I already mapped out another 4 or 5 equally sized subreddits with similar target audience that I'm going to do these "24 hour give-away's". But again, in a timely manner. Redditors will catch on to your scheme if you keep spamming the same thread in multiple subreddits, especially related subreddits to one-another since some users from one subreddt may frequent the other and recognize your posts.

Any input?

Basically my main questions are:
- Now what?
- What are your thoughts on using Gumroad.com to build your list?
- In terms of a worthwhile email list, where does the number 3,000 fall under? Not enough, good enough, a lot? I honestly have no clue.

Thanks everyone for reading!