rajio
rajio.ppy.sh, often referred to as rajio, was a request-based online radio service run and hosted by peppy as a side project to osu! in 2008. It allowed people to queue up songs of their choice to be played in a global broadcast.
Service
The way rajio functioned mirrors that of contemporary Discord music bots such as Ayana and FredBoat. Upon visiting the website, users could search for songs from peppy's personal music database to be added into the radio's queue — this database was estimated to be around ~400 GB in size, mostly comprising of J-pop/anime/video game songs.1
As rajio didn't support fetching songs from external sources such as YouTube, it was not possible to add songs that were not in the database into the queue. Due to bandwidth limitations, the service was only able to handle 6 concurrent users at a time.
Decommissioning and brief revival
rajio initially ran for a couple of years before being shut down in 2010.2 A year later, due to increased community interest, peppy brought rajio back to life along with a new, dedicated #rajio channel in the osu! chat.34 This revival only lasted for a brief period before the service and the chat channel were gone for good.
References
Blog post by peppy (2008-10-08): "rajio ahoy" ↑
Tweet by peppy (2010-07-03): "@aqua321
rajio has been out of action for a while now... will be back someday!" ↑Tweet by peppy (2011-04-18): "looking at the possibility of bringing rajio.ppy.sh back to life due to a lot of people showing interest in it recently!" ↑
Forum reply by Cyclohexane (2011-05-06): "No, really it'd be good to have. Especially with the newly born #rajio." ↑