Runescape, which is owned by Jagex, has been around for quite a while now, although in the last couple of years, Runescape has really taken off, some of the more old school Runescape players will remember the original Runescape, now named "Runescape Classic" or RSC.
Despite it, well not even being very long ago that it was around, Runescape 2, which the version you more then likely know, was released, so obviously pretty much everyone transferred over to play the new Runescape, of course there are still some players who play classic.
The major change, was when Jagex made it so anyone can play Runescape two, but only members can play the original Runescape, this was one of the first problems that many players faced, but afterwards, Runescape classic then closed it's door's to new members, so you were only able to play RSC if you had logged in within the previous 3/6 months.
There was some rumours about Jagex opening up RSC for players to host their own servers or something very similar, IE they'd have to pay x amount every month to Jagex to have their own Runescape classic world, I'm assuming that would mean they'd be able to control everything, but I doubt you'd be able to play the same character on 2 Runescape classic worlds.
This does seem like a very smart move for Jagex, there are many RSC private servers out there, but not a single one of them even comes to close to how good Runescape Classic was, there are still a lot of videos on YouTube if you want to check out some Classic player killing / game play.