We received 10 subscribers in 2 days from start our prelaunch campaign. Mostly from IndieHackers and ProductHunt, but also Twitter works very well.
Community on ProductHunt and IndieHackers are awesome, helpful and very open Try it in your promotion campaign.
Summary: We are still very motivated to finish our product, and we are working on it 10x time faster now! Thank you all for support, it's very important for us!