Look, people have gone back to College, Uni, School, work etc etc. since September. That's normal and every gaming community ever, will be somewhat affected by these more important commitments.
I've only been here since .86 but even though I can see that the population is declining, it's no surprise when ever-increasing numbers of "better" and online-enabled games are coming out which - people with the capable computers - will want to play. Right now the server is pretty boring for me. I, along with many others have burnt it out through putting shear hundreds of hours into various characters. It was fun while it lasted but the community is a bit of a mess at the moment due to the incessant whining and rage that seems to surge through some of the members for whatever reason they may have. The update is still nowhere to be seen and from what I've heard, even the staff team are getting tired of the game.
It's normal and Disco has more than run its course. There will probably be a slight increase if the update ever drops and when half term and holidays arrive but don't expect a miraculous turn. I haven't even seen it go about 90 for a couple of weeks now.