I guess how I "discovered" OS is what inspired me to make it. I used to frequent /r/tipofmytongue which is a subreddit where people describe songs they're trying to remember and others reply with the name/artist. I saw a random comment saying someone should make a browser based MIDI sequencer to make it a lot easier and I was like, I know how to do that! It was very lucky timing since audio support in browsers was brand new at the time, and I was on winter break and didn't have anything to do.
There were already full online DAWs like Soundtrap back then so I didn't expect anyone would use it for more than short tunes, I think the limit was 8 measures or something at first.
I found this site in like 7th grade while trying to find a free music-making site that wasn't blocked on the school laptops, and OS was the only site. I had a different account that year tho, so I've been here for a year longer than what this account says. But, yeah. I think I'd say I'm pretty glad to have found OS. Because if I never got OS, I probably would've never continued to make music. I probably wouldn't have gotten Discord, and wouldn't met so many of the friends I met on Discord.
Back in 2021 I had a virtual piano player that took midis and played them on your keyboard and I wanted a place to edit them, being 11 I searched up "online midi editor" and amongst a few other sites I found online sequencer. I never made an account until two years later though, and I never really started making music until a year and a half after that.
Felt like Soundtrap was too limiting so I tried searching online for other options, found this site and thought it was alright but not amazing... but that was back in 2019 when the sequencer was still relatively basic