I thought Runescape was the most played, not most popular. WoW's most popular if I'm correct. It's that way cause everybody played runescape but got bored and quit, but accounts practically dont ever get deleted.
classic rs is on so old wildy and stuf if u r a mem u can log on and play it (between 1st of june and 15th) then u can play any time if u r still a mem