Twitter founder Jack Dorsey has received a $2 million bid for his first tweet that he has autographed and put up for auction.

"just setting up my twttr," Dorsey had tweeted on March 21, 2006. On Friday he posted a link to "Valuables @Cent," an online marketplace for tweets where investors or collectors can "buy and sell tweets autographed by their creators."

The top bid for Dorsey's tweet has been offered by Justin Sun, the founder of TRON, a platform for blockchain, the technology underlying cryptocurrencies. He also heads the BitTorrent streaming platform.

"The creator of a tweet decides if they would like to mint it on the blockchain, creating a 1-of-1 autographed version," Valuables explains.

Buying a tweet means purchasing "a digital certificate of the tweet, unique because it has been signed and verified by the creator," Valuables stated.

In Dorsey's case, the tweet itself remains visible to all, so long as he and Twitter leave it online.

Similar online sales of iconic digital events from National Basketball Association games have already been held. The short videos can be seen for free on the internet but a blockchain-backed "Non-Fungible Token" (NFT) is generated to guarantee the identity, authenticity and traceability of the video, confirming its value.

NBA Top Shot claims to have generated more than $200 million in transactions this year, according to Dapper Labs, which has formed a joint venture with NBA to create Top Shot.

Prestigious auction house Christie's had also last month sold an entirely digital artwork reflecting the increasing acceptance of digital products.