My startup failed, I'm starting something new. Is it OK to let my first startup subscribers know about my next startup?

100%. Many companies "Pivot" and when they do, they let their current users know that the service is shutting down - but that they're now moving onto something new (or launching a new company).

Flowtown (my last company) did this 3 times. We even leveraged users to test the new product before we made it public.

Just be respectful of peoples time/email and only send to them if they opted in to receive company updates.

What's the time differential? If it's a logical next step, it's probably ok. If it's a complete shut down - or an asset sale (which would mean that the email list is owned by the acquiring company) - or longer than say 4-6 months, I would say no.

That being said, if you are in the process of shutting down the first company, there is nothing wrong to asking your users if they are open to hearing more in the future.

If your new thing would be of value to your subscribers - then sure.

Let them know "WIIFM?" in language that makes sense to THEM (in other words - use good marketing).

Assuming the product/service + the message + the offer is a good fit it won't be considered spam. Give them a chance and a good reason to opt in to a new list for your new project. And remember to monitor your stats (open rates and CTR).

Let me know if I can help in any way.

Best of luck on your new venture!

An attitude towards 'failure' is very important and often determines how the society accepts innovation all together... In many successful places failure is like a shevron of experience - and that's how it should be. So you are much better off after your first startup failed.
But if you know that your audience is seeing it differently, then better not to approach them right away. Otherwise you will be caught in discussions 'how is this one is better than that other one'... And this is a waste of time:(

As long as it's done in a respectful manner, I think it's perfectly fine.

Some great tips above. Those who have followed me for a while online have witnessed many ideas I have began to develop and then tossed by the wayside. Many domain names and Twitter accounts archived or deleted. There is no problem with transitioning your previous customers to your new venture. You just want to be careful that you do nothing that asks to much of them or creates any confusion. If your previous subscribers were paid, I would suggest offering them some sort of a discount. If there is anything overlapping, don't ask them to pay again. Give them 2.0 for free.

I am glad you decided to move on. As Presbyterian Minister, Speaker and Columnist puts it, “The path to perfection, it has been said, leads through series of disgusts.” Announcement of your next start-up can be done in the following ways and not limited to newsletter.
1. Engage Other Communities Too: Many companies decide to precede their official launch with a ‘soft launch,’ in which they share a beta version with a select audience. Share your beta with fellow entrepreneurs through local accelerators or co-working spaces. Alternatively, post your beta start-up launch on platforms like Product Hunt and Hacker News. This offers a great way to introduce yourself and get some useful feedback from an engaged and knowledgeable audience. But beware, while Product Hunt and Hacker news are great, they are also extremely saturated, so make use of other platforms like betabound, promotehour, and erli bird too. Also, try start-up and developer communities on forum sites like Reddit who are more than happy to offer their two cents worth. Just beware of the trolls. Soft launches offer insights into how your product will be received and unbiased feedback which can help you fix bugs and improve elements such as UX and design. Creating a buzz before your launch is important. It allows you to build out your audience, bulk out your social channels and show traction at an early stage when you go live. If people have never heard of you, and you launch, it is a non-event. However, if you have been mingling, networking, sharing betas and marketing content then people are much more likely to care when the big day comes.
“Your launch should be like the release of a new film – you need to show a series of trailers before you finally get the movie in the theatre,” says Dea Wilson, founder of Lifograph. “Don’t keep your start-up secret while working on it. Always talk about it as if it is already launched and you want feedback from people. By the time you launch people already know what you do, and they already know the brand.”
2. Contact the Media but Share the Right Stories: When you do decide to reach out to the media, you should not pitch them your start-up launch in itself. Journalists are looking for stories which readers will find interesting, useful, and inspiring. Every start-up launches. The point is to show journalists what is different about your company, not what is the same. Emma McGowan from Tech.co says “Sorry to be blunt, but no one really cares about your company launching outside of your family and friends. If you want coverage, you need to be doing something interesting and newsworthy. Simply launching a start-up doesn’t fit either of those categories.” If you want to grab the attention of journalists, you need to tie your announcement into a bigger trend. Another idea is to show them another aspect of your company, your team or your culture which is different, interesting, and newsworthy. For example, if you are trying to improve enterprise communications, why not open with a data point about how many hours are wasted trawling through emails each day, backed up by your own surveys. If you want to reduce CO2 emissions with your tech, why not link to the catastrophic risks global warming poses to humanity, and a recent news story on that theme.
3. Find Your Angle: Pitching to journalists is very time sensitive. Always be on the lookout for other news stories that make your company more relevant. Journalists love hard data, infographics, white papers, and studies. Be sure to offer them this information, as an email attachment. Or let them know that you would be happy to share more with them. Be sure to spend the time finding the right journalists to pitch your story to. Use Muckrack or Cision to check journalists’ ‘beats’ –the areas they write about — and if possible, try to mention at the start of your personalized pitch why you think your story would be relevant to them, by linking to a previous story they have written.
4. Build out Your Network and Give More Than You Take: In the world of Silicon Valley and further afield, networking means giving more than you take. This means building positive relationships — and trust — over time. Do not just interact with people when you need something from them. Build positive relationships by being active in your communities, attending events, offering mentorship and expertise on your industry. Another option is to create content in the form of blogs and thought leadership articles and engage with others on social media. Dea Wilson says she tries to check in with each of her contacts regularly. A good way to widen your network organically is by bringing on strong advisors from the outset. Being able to tie your company name to a well-respected figure in your industry improves your social proof. The social proof thus improves your chances of being noticed by investors, or the media. These advisors will also bring with them their own networks. Use advisor’s connections to create a buzz around your launching start-up.
5. Hold an Event but Do not Call it a Start-up Launch Event: Even the biggest companies struggle to fill seats at launch events. Filling seats is especially difficult in busy tech hubs with hundreds of events happening every day. As a means of getting assess on seats, while building out your network, why not hold a community appreciation event rather than calling it a launch? Create an event that offers as much value as possible. Catch eyes with a trendy venue but woo guests with more than just a couple of glasses of mid-range prosecco. You should provide valuable content too. Providing a workshop or speaker which can give real takeaways will attract people for the right reasons. They will also be more receptive to a short presentation about your product at the end of it all.
Besides if you do have any questions give me a call: https://clarity.fm/joy-brotonath