It has been the biggest craze in investment of the last two years - the idea that creating your own crypto-currency through an Initial Coin Offering (ICO) is the route to riches.

But now an academic study has revealed just how many of these ICOs end up disappearing without trace after a short while.

A Boston College research paper entitled Digital Tulips finds that fewer than half of these projects survive more than 120 days after the completion of their sales of tokens to the public.

The researchers arrived at this conclusion by examining the official Twitter accounts of the crypto-currencies. They found only 44.2% of them were still tweeting after that four-month period and concluded that the rest of the ICOs had died.

Mind you, the study also finds that the ICO gold rush is continuing, with $12bn raised from more than 4,000 ICOs since January 2017 - and those investors who got in and out quickly made big profits.

Maybe it is not surprising then that the excitement about crypto-currencies and the blockchain technology which underpins them continues to reach new heights,

One example is an advert which has probably bemused millions of viewers of ITV's World Cup coverage. The ad, played during half-time, features a cosy home scene where all the domestic appliances appear to be trading energy with each other.

A caption says: "Hdac Technology is building the future with the blockchain solution." Hdac, a South Korean blockchain business, must be paying a fortune to place the adverts in the most expensive slots of the year.

But even if anyone understands what on earth they are about, it seems unlikely they are going to rush out and buy a blockchain to get their microwave to talk to the kettle.

Maybe, however, they will think they need to go on a course to understand this brave new world. If so, two of Britain's most prestigious academic institutions can help.

The Oxford Blockchain Strategy Programme, run by the University and its Said Business School, offers you a six-week online course for just £2,200, promising you will emerge with "a comprehensive understanding of what blockchain is and how it works".

On top of that, you get a certificate of attendance from the Said Business School as well as "access to a global network of like-minded business leaders and innovators".

The Financial Times has been reporting on an even more exciting opportunity, a London School of Economics course in "Cryptocurrency, Investment and Disruption" - and this comes with a bargain price tag of just £1,800 for the six-week online programme.

When the reporter has the temerity to suggest that the programme seems to be lacking in academic rigour and may be tempting people into the unregulated world of crypto-trading, she is told this by one of the course leaders: "Stop being a journalist and just think. You're citing marketing material as if that were the ultimate truth."

Judging by my inbox, the volume of marketing material about crypto-currencies and especially blockchain is expanding at an exponential rate. And I have a sneaking suspicion that finding the "ultimate truth" in this mountain of hype is not going to be easy.