Twenty years ago this month, the SMS text message was born in London. "Merry Christmas," typed software engineer Neil Papworth, using a personal computer, to his friend Richard Jarvis, an employee at Vodafone, using a mobile phone.
One year later, Nokia introduced the first mobile phone that allowed text messages to be sent within the same network. The technology grew slowly until 1999, when text messages were finally deliverable across different networks. That, along with the growth of mobile phone usage, turned text messaging into a phenomenon.
The text message has had a good life - two decades is a long time in the tech world - but it's slowly being replaced by another phenomenon: WhatsApp, the mobile messaging app created by a start-up business from California in 2009.
It works the same way, mostly. You still type messages with shorthanded spelling and weird acronyms, and you're still annoying the person sitting across from you during dinner with it, but it's free (after a one time 99 US cents download fee), assuming you have access to the internet.
And people like free. WhatsApp is the top overall paid app in the Apple App Store in 119 countries; it delivers more than 10 billion messages a day; and the big tech blogs estimate WhatsApp's user base at more than 200 million (some say 300 million).
SMS text messaging numbers, predictably, have dropped as a result. The New York Times reported early this year that text messaging is declining in most parts of the world. In Hong Kong, there was a "steep decline in text messaging on Christmas Day ", according to figures released by local mobile companies. It's safe to assume the figure will drop again this Christmas.
Yes, Hongkongers love WhatsApp - even more so than the rest of the world. When the app's co-founder and chief executive, Jan Koum, visited the city recently, he confirmed that, with more than three million registered WhatsApp users, Hong Kong was one of WhatsApp's "three largest markets".
That's 45 per cent of the population. The extent to which WhatsApp has penetrated Hong Kong mainstream culture can't be understated. It seems that everyone is on it.
"It's become the go-to method of communication for young Hongkongers," says Vanessa Lai, a public relations executive who sent out a mass WhatsApp message to journalists around Hong Kong the night before a media event last month. "I use it to replace the dreaded 'follow-up reminder call' with the media."
Kenneth Yan, culture writer for Oriental Daily, says most people in the Hong Kong Chinese media circle - reporters, editors, and public relations executives - prefer to use WhatsApp to communicate. "It's just faster and easier," he says. "People may not check e-mails, people may be too busy to answer phones, but everyone talks on WhatsApp."
It's not just the white-collar world that's using it. When my toilet clogged up last week, the plumber who fixed the problem departed with the message: "If you have any more problems, feel free to WhatsApp me." He was old enough to be my grandfather.
Earlier this year, when attempting to reach Hong Kong rapper Chan Kwong-yan (aka MC Yan of LMF and 24 Herbs) for an interview, I was told: "It's best to WhatsApp Yan; he doesn't really respond to e-mails or calls".
WhatsApp has become so ubiquitous that companies big and small are queuing up to work with it. In September, local mobile carrier 3 Hong Kong launched a "WhatsApp roaming deal" - the first deal of its kind for either company - which provides customers unlimited use of WhatsApp even if they have a limited data plan.
This month, TechCrunch reported the rumour that Facebook, the largest, most successful and influential start-up of them all, is interested in buying WhatsApp.
Garron Kertnen Chiu, a business development executive at digital advertising agency NDN Group, says companies are adapting to "WhatsApp culture" by creating "ad blast bots".
"It's basically like cold calls from telemarketers, but instead of calling, it's a mass WhatsApp message sent out to an entire database," he says. The success of WhatsApp has prompted companies to launch similar chat apps, hoping to take a slice of the pie. Last year, Chinese internet service portal Tencent launched Wexin (Chinese for "micro-message"), and it already has more than 200 million users on the mainland. In Japan, the chat app of choice is Line, created by Japanese internet service provider NHN Corporation. It has more than 70 million users.
Backed by major corporations, both Wexin and Line strive to be more than just a text messaging app, but a full-on social networking platform.
If WhatsApp is worried about the competition, its founder isn't showing it. "We want to be really good at doing one thing and doing it right, instead of trying to do five things," says Koum. "We are keeping the product simple and clean."
Whether or not WhatsApp continues its dominance, it seems standard SMS text messages are an endangered species.