Several weeks ago, a friend of mine asked me to help him create a Codeforces account.
At first, I was a bit confused: his English is not bad, of course, and he has already registered for an Atcoder account, which means he isn't new in competitive programming websites. However, after a while, I realized something: the CAPTCHA for registration is linked to Google, which is banned in (Mainland) China. There were a few methods to bypass the IP blockade several years ago, but most of them are considered as illegal activities now.
I know there are many other problems(in other websites, perhaps) caused by blockade，but stopping the Great Firewall is an even more difficult choice as it is said that some Chinese users tend to go to extremes when they get complete freedom.(perhaps related to political reasons?)
So, I sincerely suggest Codeforces provide a more convenient way for Chinese users to register, as a significant number of competitive programmers are from (mainland) China.
（Sorry for my poor English :P)