In recent weeks, bitcoin mania has crept to the fore. Having started the year at US$750 (24,500 baht), it was trading at $16,840 on Coindesk as of late yesterday evening.
The famously volatile currency's market capitalisation now stands at around $280 billion, ahead of Visa and even besting the world's largest bank, JP Morgan, at one point.
Over the weekend, bitcoin futures topped $18,000 in their trading debut on the Chicago Board Options Exchange. The CBOE contracts, set to be followed by similar offerings from CME Group Inc this Sunday and Nasdaq Inc next year, make it easier for mainstream investors to bet on the cryptocurrency's rise or fall.
Jaw-dropping predictions have invited rampant speculation, with former hedge fund legend Mike Novogratz saying bitcoin could "easily" reach $40,000 in 2018 and other "bitcoin bulls", including cybersecurity pioneer John McAfee and Paypal's Wences Casares, claiming it could hit $1 million within 5-10 years.
But what exactly is bitcoin? To answer that question, you need to go back thousands of years into the history of money.
"Nobody knows how old money is. It is certainly older than writing," said Tony Campbell, director of professional development at DFDL, which specialises in legal, tax and investment advice focused on South and Southeast Asia.
At first those transactions took the form of barter, where people would exchange goods and services that everyone agreed were of equal value. Shells and beads followed, then came precious metals.
Precious metals were successful because they combined some of the most important characteristics of money: they are scarce, easily transportable and relatively easy to divide into smaller pieces. All of those qualities made them universally valued.
But precious metals have two problems: large amounts of gold and silver coins and ingots are not easy to carry around every day, and because they are not difficult to steal, you have to spend a lot of money protecting them.
Then someone came up with a bright idea: you can deposit your gold with someone trustworthy -- a bank, for example -- which would then provide a piece of paper as evidence of the gold deposit. That meant you could trade the paper, rather than carrying around the gold. As a result, money changed its form again and became paper currency.
It took paper notes about 400 years to catch on as an idea. But when they did, notes became the only acceptable form of money. Banks and governments around the world issued the notes which, after a while, were no longer backed by gold, but simply by trust in the government or the institution that issued them.
Then, about 60 years ago, we saw an even newer form of money in the form of plastic cards, Mr Campbell said. Money became lines of computer code, recorded in transactions in the ledgers of banks and companies like Visa, MasterCard and American Express. And this change, together with other larger forces at work, led to the rise of bitcoin.
Bitcoin grew out of the global financial crisis that began in 2008. At that time, trust in institutions and the governments that regulated them were at an all-time low.
In the midst of this crisis, someone going by the name of Satoshi Nakamoto published a paper that outlined how a peer-to-peer electronic cash network could be created without the need to trust banks or financial institutions. Shortly afterwards, he published software that allowed people to start building the bitcoin network. Bitcoin, thus, was born.
The easiest way to describe bitcoin is to say that it is digital money. But it is much more than that.
Bitcoin is a technology and an international system of payment and exchange. The currency is decentralised: it does not rely on banks, governments or even a central company. No one owns it and no single person, corporation or government controls it.
Instead of physical coins, the technology uses a combination of mathematics and cryptography to confirm transactions and reward "miners" for doing so. Bitcoin has begun to acquire some of the basic characteristics of money.
Bitcoins are scarce. There will only ever be 21 million of them, nearly 17 million of which have already been mined. Bitcoin is divisible -- each one can be divided into 100 million smaller units, called satoshis. And they have value.
You can buy and sell bitcoin on exchanges, including three regulated and AML- and KYC-compliant exchanges in Thailand, and you can spend it -- including at Bangkok's oldest noodle shop. There is at least one ATM in Bangkok where you can conduct bitcoin transactions.
And blockchain, one of the technologies that underlie bitcoin, is being used across an increasingly wide range of industries.
So, what's next? There is Ethereum, Litecoin, Dash, Omisego and more than 1,000 other cryptoassets. This year has also seen a spike in ICOs (initial coin offerings).
With cryptocurrencies' rapid ascent, financial institutions, governments and regulators are finally taking notice. That is likely to mean an interesting year ahead for bitcoin.