The first ever tweet, "just setting up my twttr," is up for sale after Twitter boss Jack Dorsey listed his famous post as a unique digital signature on a website for selling tweets as non-fungible tokens (NFTs).

The post, sent from Dorsey's account in March of 2006, received offers on Friday that went as high as $88,888.88 within minutes of the Twitter co-founder tweeting a link to the listing on 'Valuables by Cent' - a tweets marketplace.

Old offers for the tweet suggest that it was put for sale in December, but the listing gained more attention after Dorsey's tweet on Friday.

NFTs are digital files that serve as digital signatures to certify who owns photos, videos and other online media.

Dorsey's 15-year-old tweet is one of the most famous tweets ever on the platform and could attract bidders to pay a high price for the digital memorabilia. The highest bid for the tweet stood at $100,000 at 0125 GMT on Saturday.

Launched three months ago, Valuables compares the buying of tweets with buying an autographed baseball card. "There is only one unique signed version of the tweet, and if the creator agrees to sell, you can own it forever."

A tweet's buyer will get an autographed digital certificate, signed using cryptography, that will include metadata of the original tweet, according to the Valuables website. The tweet will continue to be available on the Twitter website.