The co-founder of Twitter is selling the rights to his first-ever tweet, with bidding reaching the US$2.5 million (NZ$3.5 million) mark.
In March 2006, Jack Dorsey posted "just setting up my Twitter" on the platform, which is being auctioned off as a non-fungible token.
Better known as an NFT, the digital certificate specifies who owns online media - in the form of photo, video and other digital content.
This effectively verifies authenticity and ownership of the product.
The winner of the collector's item will receive a digital certificate signed by Dorsey and the metadata of the first tweet in the company's history.
Valuables by Cent is running the sale, a website also launched by Twitter, where people can buy and sell tweets in the digital form.
"There is only one unique signed version of the tweet, and if the creator agrees to sell, you can own it forever," Valuables says.
So far the CEO of Bridge Oracle, Sina Estavi, is currently leading the bidding.
An NFT is becoming an increasingly popular way to sell digital items such as art and music.
The NBA is another major company to get involved, with video highlight clips being sold - allowing people to collect clips as they would with trading cards.
Despite the 15-year-old tweet being up for sale, it will remain online for all to see.