Reddit user eli0tz has brought attention to Google Ads seemingly blacklisting Ethereum as a keyword. The user said they have been using keywords containing Ethereum for the last 6 months without issue, in order to get more visibility for their smart contract auditing services; however, since January 9 they have noticed a change, and now it appears that ethereum has been blacklisted.
https://all-stocks.net/ethereum-blacklisted-in-google-ads-according-to-reddit-reports/