How to Use Bitcoin’s Blockchain for Advertising

TD Ameritrade, the online broker for online stock trading, long-term investing, and retirement planning, planted their literal flag (in ASCII) on Bitcoin’s blockchain, effectively making an advertisement for themselves.

In a recent post, the online broker said they sent 68 Bitcoin transactions to create a digital flag with its logo on the Bitcoin blockchain. “With a part of the blockchain called OP_Return, which functions like the memo space on a check, simple messages and characters can be placed within transactions on the blockchain. By linking 68 individual transactions, with 80 characters per transaction, we were able to create the larger image,” they write.

“The blockchain is an amazing piece of technology. And we’re proud to be part of it. Forever.”

Thanks to the famed feature of blockchain, its immutability, this flag is now preserved on it forever. According to data from Blockchain.info, no Bitcoins were actually transferred through these transactions.

The official Bitcoin wiki page notes that OP_Return can be used to convey information. Back when it was introduced in 2013, the idea was that it should be used to include some messages in the blockchain. But the Bitcoin Core 0.9 release in 2014 states that data storage is far from endorsed. “Storing arbitrary data in the blockchain is still a bad idea; it is less costly and far more efficient to store non-currency data elsewhere,” the release says.