Your music is under attack, you must liberate it! A mysterious entity is absorbing and corrupting your music before your very eyes. You must battle through your own song collection, discover items, customize your ship and fight boss enemies to liberate the Symphony of Souls and reclaim your music!
Most popular community and official game content for the past week.  (?)
What does popular mean?
It means the content you're seeing has been rated up more than it has been rated down for the given time period.