Very good question I'am not sure if Steemit itself blocks any countries... Might should look into what countries block Steemit or have little access to internet. I can't give a full list of countries that do this but most of the time things like google, twitter, facebook, instagram and others are not actually blocking other countries but other places are blocking certain content off of these sites, major censorship is happening all over the world right now based on our personalities, where we live and more.. Every site wants as many users as they can get and thats why most give into censoring us (they get money from the government by doing this and more money for every user they can get) This is why i like steemit so much because i do see users from all over the world and I feel like I've never been censored nor other people. Very good content on here.. Let me know if you find out anything new I'd really like to know! Excellent question!