Today I received this incredibly offensive talk message from an unrated account (also with an offensive username), which attacks me based on my national origin:
I strongly suspect that I am not the only Codeforces user receiving such messages recently (I don't think I am particularly notable in any aspect as a Codeforces user, and I cannot think of a reason why I might be specifically targeted); if you received similar messages, let me know in the comments.
I am aware of the "block user" feature and the ability to require a minimum rating for users to send messages to you, but it is not very well-known and is simply insufficient.
Update: after receiving the message, I set a "at least newbie" setting for users to send talk messages to me. However, two unrated users still managed to message me after the blog post was created. This seems to be a Codeforces bug.
I therefore request that unrated users be prohibited from sending talk messages. We should also probably consider the idea of adding a filter of some sort for profanity.