PPD is a free rhythm game.
If you sign up, you can upload scores and do more.
You can upload score which was created with PPDEditor, replace uploaded score, creating score information, and upload score at specified datetime. Players can get updated information of score which was uploaded on official server in PPD application.
All difficulties of all scores which were uploaded on server have each ranking. If you rank in, you can get ranking point and PPDY. PPDY is money which is used in PPD community.
If you want to change PPD application appearance, you should get/create Mod. Players can get updated information of mod which was uploaded on official server in PPD application. You can get uploaded scripts which can be applied for score to custumize PPD bevavior.