As you'll probably have heard by now, Facebook has bought WhatsApp.
Our new infographic above gives some great context to why Facebook might have done this.
But what's the story behind the numbers?
It's clear that Facebook wants to become a mobile-centric platform, and to us, the WhatsApp acquisition seems like a very smart move.
Although Facebook's Messenger app has been around for some time, it hasn't gained the same level of traction of other, standalone chat apps like WhatsApp, WeChat or LINE.
This partnership gives Facebook access to one of the world's most active, real-time conversation platforms out there - something they'll be able to tap into from a variety of angles.
From an audience perspective, Facebook's sheer scale and financial base should be good news, allowing WhatsApp to roll out new features more quickly and easily than before.
From a marketer's perspective, WhatsApp is a great addition to the Facebook portfolio.
On the one hand, Facebook will now be able to tap into a huge wealth of data about real-time social interactions - especially on the go - and understand more about the fluid dynamics between people in a way that its existing platform doesn't do.
From a services perspective, it's not clear how Facebook will monetise this new channel, but our hope is that it won't be through advertising.
Interrupting our content feed is one thing, but interrupting private, one-to-one conversations is likely to be much less welcome - or effective.
Our take on this is that monetising real-time customer service offerings for brands - i.e. WhatsApp as an always-on, large-scale mobile support channel - would be a great place to start.
We imagine there will be a foray into a replacement for SMS marketing too; with WhatsApp already delivering more than twice as many messages as SMS does around the world, it is clearly a huge opportunity.
However, Facebook will need to be careful that the platform doesn't descend quickly into spam and unwanted intrusions; there are plenty of other mobile chat options out there, and they're just a few clicks away.
When it comes to the chief of the chats, WhatsApp is still a little way behind global leader, Tencent's QQ, even if the latter is still primarily China-based:
WhatsApp is still ahead of Tencent's real mobile chat play - WeChat - but China's hottest social property is still growing quickly, and its global base is accelerating too - we'd not be surprised if WeChat surpassed WhatsApp on a global basis in a year or two.
LINE and KakaoTalk keep active user data a relatively closely guarded secret, but our understanding is that both hover around the 100 million active users, with the main focus in Asia, especially Korea, Japan and Indonesia.
The Asian angle will certainly be an important one for Facebook in this acquisition though; with APAC social penetration currently sitting around 25%, there's still huge potential for growth, and it's clear from the mobile subscription numbers in the region that mobile is the way forward:
(read more in our new Social, Digital and Mobile in APAC report)
What's more, with WhatsApp currently adding 1 million new users per day, this new part of the Facebook family is definitely one of our hot tips for 2014.
Give us a shout on Twitter if you'd like to talk through what this means for you and your brand in more detail: @wearesocialsg