Many many more fake accounts are being blocked,
about double the number of "CAPTCHA" failures:

After they do get past the CAPTCHA, about 80-100 signup attempts a month from Russia are being blocked
(I guess they're not reading the message).
After people do manage to sign up, about 3 out of every 5 new accounts are fake
(they are easy to spot, as they never solve any puzzles)
(strangely enough, some of these fake accounts log in later, and change their country to a random new one)