Jack Dorsey is the latest entrepreneur to jump on the non-fungible token (NFT) bandwagon, listing his first ever tweet for sale. "Just setting up my twttr," reads the post from March 2006. The highest offer is currently from Sina Estavi, CEO of Bridge Oracle, for $2.5M. While the buyer will receive a certificate - digitally signed and verified by Dorsey - the post will remain publicly available on Twitter (NYSE:TWTR) even after it has been auctioned off.

What is an NFT? It's a type of cryptocurrency - run on Ethereum blockchain - that's used to represent a unique asset and are valued as collectors' items. They are usually art, but can also be a meme, GIFs, songs, videos or items in video games. NFTs work like other speculative assets, where buyers hope that the value of it goes up, so it can be sold for a profit. Investors, however, caution the market could represent a price bubble.

Bigger picture: A video by a digital artist who goes by "Beeple" recently sold for $6.6M and a crypto art rendition of the Nyan Cat meme sold for $590K. Musicians like Grimes, 3LAU and the Kings of Leons have even dabbled in the sector. That's helped NFT marketplace OpenSea grow its monthly sales to $86.3M in February, while auction house Christie's just launched its first ever sale of digital art.

NFTs seem to be a natural extension of Jack Dorsey's advocacy of cryptocurrencies. He's been displaying "#bitcoin" in his Twitter bio for some time, while his digital payments company Square (NYSE:SQ) scooped up another 3,318 Bitcoins in late February (it purchased 4,709 in October 2020). Square's Cash App is also a major venue for retail investors to purchase crypto, while the company last week started operations of first industrial bank.