That means that even companies with legitimate cryptocurrency offerings won't be allowed to serve ads through any of Google's ad products, which place advertising on its own sites as well as third-party websites. This update will go into effect in June 2018, according to a company post. "We don't have a crystal ball to know where the future is going to go with cryptocurrencies, but we've seen enough consumer harm or potential for consumer harm that it's an area that we want to approach with extreme caution," Scott said. Google's hard-line approach follows a similar ban that Facebook announced earlier this year. While the crypto-currency boom has produced a lot of excitement and wealth, it's still a largely unregulated space and has spawned countless high-profile scams.

https://www.cnbc.com/2018/03/13/google-bans-crypto-ads.html