But it is already allowing consumers to test-drive cars from their couch via its apps.

As the world's most popular social media network - it now has 2.07 billion monthly active users worldwide - attracts more people to engage with the world via its apps, it becomes another marketplace where car makers and dealers want to be.

In 2017 Facebook added car listings from automobile dealers to its Marketplace tab.

Facebook's head of global auto strategy, Thomais Zaremba, who has been in Australia this week meeting with car dealers across the country, tells Fairfax Media that used cars are the top-selling item on its marketplace.

Most cars for sale have been owner listings and for free, says Ms Zaremba, who previously worked as head of digital media and marketing for Ford.

But car dealers are now starting to list. And as more of them do, Facebook naturally wants to make money out of it.

While Facebook isn't letting people process transactions on its platform just yet, it is expanding the number of cars it can help sell by partnering with online sites like Cars.com, and others.

"Our platform gives you the ability to reach 15 million Australians [via the Facebook app] with a very personalised message," Ms Zaremba says.

"We're giving automakers the ability to target specific consumers with specific messages."

Those interested in a dealer-listed car they see on Marketplace will be prompted to contact the car dealer directly via the Facebook Messenger app.

Aside from the 15 million Australians using the Facebook app, 13 million Australians use the Facebook Messenger app, and another 9 million are on Instagram.

They are not just there for a minute or two - users spend nearly an hour every day scrolling through Facebook status updates, lnstagram posts, or chatting on Messenger.

"That gives marketers a completely new tool to speak with consumers and it allows them to address one-to-one via chat box experiences the entire consumer journey," Ms Zaremba says.

It can be "anything from changing the vehicle sales process ... to managing service scheduling ... to owner loyalty conversations, to allowing consumers to ask [the car marketer] a specific question."

Are they wanting to get into the business of listing and selling cars next? "No," she says.

"At least not until autonomous vehicles come to life and even then we won't be the primary drivers of that, automakers will be."

Facebook's chief operating officer Sheryl Sandberg recently moved to calm down a very nervous car industry keen to protect its turf, telling them in a speech in Germany that Facebook is the only Silicon Valley company not building cars, and doesn't want to be in that space.

But new players are fast moving in. Take for example British inventor James Dyson - the face behind the popular household vacuum brand - who is investing ??2.5 billion on electric cars that will launch in 2020.

So why isn't Facebook doing the same? "It's not what we do," Ms Zaremba says. "It's not our core business."

Of course, once a company builds scale, there's nothing to stop it making acquisitions and moving into that space.

Facebook won't share numbers on how much revenue it's collecting from its early foray into auto-ads. But its latest global figures do indicate advertising revenue is growing.

Facebook made annual revenue of $US10.3 billion for the year to September 30 2017. Third-quarter ad sales rose 49 per cent to $US10.1 billion, while mobile ad sales also grew to $US8.9 billion, or 88 per cent of all sales (???up from about 84 per cent of advertising revenue in the third quarter of 2016).

Facebook now has more than 6 million advertisers, while the company's Instagram service has more than 2 million.

This has room to grow further as the company further uses artificial intelligence, virtual reality and robotics to target car buyers.

"We're at a place where technology innovation is happening faster than human adaptability can keep up," Ms Zaremba says.

"We already have automotive dealers building virtual reality experiences on Oculus," she says. In 2014 Facebook CEO Mark Zuckerberg acquired virtual reality start-up Oculus VR. Now Facebook users looking for cars can "experience a test drive from your couch".

"We're just starting to see automakers fully investigate what it [marketing and dealing with consumers via Facebook] can do for their business," Ms Zaremba says.

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