I've built Pipewing.com, where I want to connect remote workers with other remote workers from the same city through 1:1 video calls. That way they can get to know each other and eventually meet in person for lunch or work.
This is the exact same pitch I used to describe my product on r/SideProject: https://www.reddit.com/r/SideProject/comments/nsttn7/i_feel_working_remotely_is_lonely_so_i_built_this/
I've posted the project previously and nothing ever happened. This time, however, it went viral for some unknown reason. Maybe the right subreddit, lucky timing, etc.
I really helped me to get the first 50 users within one day. Amazing.
What's the lesson?
You need to get lucky to go "viral" on Reddit or other social media channels. Similarly, to start a successful business, you always need to get more or less lucky. But, if you try hard enough, some time you will get lucky. You can fabricate your own luck if you try hard enough and don't give up after the first post (or failed side project). You need to keep going.