From this month, the US State Department will implement its latest policy measure to deliver President Donald Trump's "uniform baseline for screening and vetting standards and procedures".

Anyone submitting an Online Non-immigrant Visa Application (DS-160) to visit the US will be required to provide the details of their social media accounts over the last five years.

And we have been warned that non-compliance will have serious consequences.

For the time being most Australian passport holders will be exempt from the new rules. ( ABC News: Melanie Vujkovic )

Fortunately most Australian tourists and business travellers are covered by the US Visa Waiver Program.

Under this program Australians must complete the Electronic System for Travel Authorization (ESTA) form, which gives us an option to list our social media accounts: but this is not compulsory, for the time being.

What is the goal of the new rules?

The aim of these measures is rather simple. US authorities are going to collect information from new sources and collate it with existing intelligence to enhance the screening and vetting of travellers.

And the focus for the most part is on trying to identify potential terrorists.

US authorities want the details of travellers' social media accounts because they can be subsequently used to collect a wealth of information relevant to individual migration decisions.

For example, geo-tagged posts from an applicant's social media account can be crosschecked with the details provided in an application.

Or details such as phone numbers, emails and social media followers can be crosschecked against intelligence holdings to confirm a traveller's associations with known terrorists or criminals.

These measures, while not without merit, were probably developed without a well-informed understanding of the nature of social media.

Short-term benefit

Firstly, the social media environment is changing all the time with an increasing number of specialised platforms. Many users, including would-be terrorist or criminals, are early adopters of new platforms.

A sign at a memorial on Dean's Avenue in Christchurch reads "This is your home and you should have been safe here". ( ABC News: Brendan Esposito )

For authorities, confirming that a traveller has provided the details of all their social media accounts will be problematic.

On the plus side this may act, at least in the short term, to discourage some people from travelling to the US.

Encryption can be tough to break

Secondly, the war on terror has shown that social media encryption is tough for authorities to break.

Already intelligence and law enforcement agencies find it hard to access and decrypt select communications between known offenders.

It seems unlikely that having the details of large numbers of accounts will resolve the encryption problem.

What about privacy?

Thirdly, leaks of official US information over the last two decades have created global distrust of government intelligence collection and the ability of authorities to keep private information secure.

In many cases there is a growing concern about privacy, which collectively may either result in dishonesty or avoidance.

For the time being it seems unlikely that authorities would be able to prove that a person has provided all of their details.

In some cases these measures discourage legitimate business and tourist travel to the US, which will likely have economic impacts.

The US wants information on social media accounts held by visa applicants before a visa is issued. (AP Photo/Jenny Kane, File)

Can all the new data be analysed?

Finally, having more data is fine, but without big data analytic capabilities, including artificial intelligence, it seems unlikely that the true value of this information can be exploited in a timely manner.

But these changes should be viewed as a start point that will set the precedent for later changes.

In time, and with the right big data analytic capabilities, US authorities will be able to develop a detailed understanding of a traveller's life and perhaps in time simulations of how they make decisions.

It's the future

While for the time being Australians have a reprieve from the new US measures, we should all be alive to the fact that our social media activity provides a lot of information about who we are and where we have been.

Keep in mind what you post on social media. ( Unsplash: Steinar Engeland )

But just as importantly decision-makers ranging from employers to foreign governments are increasingly seeking this information to support their deliberations.

Sure, a bad drunken selfie from five years ago might be embarrassing, but an ill-thought-out social media rant could well now have lifelong consequences.

Dr John Coyne is the head of the border security program at the Australian Strategic Policy Institute.