My daughter recently start playing this game with her Kindle Fire.  I monitor her content and activity and found a fairly active portion within the community of the World of Cubes to be disturbing.  The game was fed to her as age appropriate within the age range of 6 to 10 which I have her Fire set to, she is 9.  Chat and Web access are disabled on her device.  However, scanning her Friends list brought a very serious issue to light.  That being that the username field can be edited at will.  Which led to two serious problems.

1.)  Of the users online I discovered that a significant percentage or them were named in a manner that was very inappropriate for my 9 year old.  They were full of profanity and sexual suggestions and I even noticed inquiries for potentially identifying information.

2.)  Due to this ability individualizes were even communicating with my daughter via this "feature".  Essentually using the username field to circumvent the disabled chat ability and message her back and forth.  She to was quick to figure this out as well and was actively participating in the two way communication.

Please take this issue seriously and do something about it.  For now I can contacted Amazon with the approve concerns to inform them that until this is resolved that I do not consider the game safe for the age range they are providing it to and suggested that they removed access to it from Free Time.  The game itself has obviously been removed from my daughters device and blocked for the time being and the situation used as a teaching moment for her.

As a software engineer myself I suggest the following:

1.)  Lock down the username so that it cannot be used in this manner.

2.)  Improve the profanity filter if there even is one atm.

Respectfully,

A Concerned Father.