Beware of these guys. Articles on medium are free for anyone to write and anyone can make up information on there and share it. Think of as a place for people who want to write but aren’t real writers to go and spread their message. There are some valid articles but it a company is trying to justify or promote themselves via validation of third party and list an article on medium, it is most likely an advertisement for themselves. You’ll find this alot on facebook ico ads at the moment. Don’t fall for it.