An article by Gao Linhui from Fujian Province Channel Blockchain Institute raised the issue of leaving message via blockchain transaction. The author proposes several measures to prevent Ethereum blockchain from being a free bbs. Below are excerpts from the article.
The incident was named “5490403”, which was the blockheight of Ethereum network that stored the specific transaction. Account holder of the same address later initiate another transaction at blockheight: 5496356 with the following message :

“I just want to save a copy of her letter on blockchain. To show one of the possible usage of blockchain． “

The author proposes the following counter-measures.
Although the messages and transactions of the Ethereum blockchain can be created by “smart contracts”, but the original contract code and its controller are still real entities. Blockchain cannot self-certify that all data or digital assets created by external entities are legal. Therefore, it should be a common practice for key service providers and supervisors not to endorse malicious accounts, illegal messages, spam transactions, etc.

1. In terms of message-bearing transaction, in addition to prevention of spamming and DDoS attack, proper encryption and trust management should also be applied to eliminate spreading of harmful messages.
2. As far as internal transactions are concerned, it is necessary to avoid illogical transactions like 0 tx, internal transfers within same accounts, not to support receipts and payment transaction that are lower, and to strictly limit message-related transactions and the data length of remarks.
3. As far as smart contracts are concerned, the technology is not yet very mature. It is not advisable to fork the network after a consensus system is confirmed multiple times. confirmations of the first accounting. Forking not only affects the economic value of the contract, but also drives up the operating costs of the entire blockchain network. Key service providers and supervisors must strengthen investor education and consumer protection.
4. In terms of value management and fintech application, it is necessary to anchor values of original technological value, tokens, smart contracts etc. Ripping value created by external entities should be avoided. Two-way convertibility between digital assets and fiats should be managed.
5. As far as the operators and users of distributed application are concerned, embracing supervision is the most effective method of protecting their own rights and interests. It is necessary to protect the legitimate rights and interests such as privacy rights, intellectual property rights, digital asset ownership and network use rights. We must also earnestly perform social responsibilities or obligations such as KYC and AML, anti-terrorism, anti-fraud, anti-porno, anti-violence to ensure that the personal, collective, and national interests are not violated.

Finally, it should be emphasized that the foreign identity of the relevant entities is not enough to ignore or violates existing laws. Chinese citizens or organizations should consciously obey the supervision and restriction of international law and Chinese laws and regulations when they attend oversea events.