Some years back, I borrowed Elite Beat Agents from my cousin because it looked like a really fun rhythm game (and it also helped that I saw X-Play's review on Osu! Tatakae! Ouendan at around that time frame as well), so I decided to give it a shot, and I was hooked right off the spot.
I looked for an EBA simulator about a year after, and I stumbled upon this site. Sadly, I ignored it afterwards for the most part with the assumption at the time that it would never take off...
...and then comes college when suddenly, all of the CS club there decided to go on a huge osu binge for whatever reason, and I decided to jump the bandwagon for once. Things took off from there; I attempted beatmapping, but I felt I didn't know much about the art of beatmapping to come up with anything decent.
Sometimes I take hiatuses from time to time, but when I am playing osu, I usually play a lot in a month (like, around 500 games a month, usually).
tl;dr, EBA -> osu -> "This will never take off" -> CS club osu binge -> Now.