So, I left Facebook last week. Or more precisely, I deactivated my account while I consider whether I want to rejoin.

It means I "disappear" from the Facebook universe. And, obviously, I don't know where people have eaten tonight, where they've been for the weekend, or what cute pug video they reposted. Unless, like, I actually talk to them.

Why did I leave Facebook? I had mixed feelings about oversharing, and an underlying unease about where that data went.

But much more significantly, the exposé by The Guardian of the role of Cambridge Analytica in duping hundreds of thousands of American Facebook users into sharing the details of millions of fellow Americans apparently leading to a smart targeted campaign during the US election, and another around Brexit in the UK, places a stark white light on the risks of big data in our world.

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Today, the US Senate put it starkly to Mark Zuckerberg "If you social media companies don't get your act together, none of us will have any privacy anymore", and they said what we are all thinking – "these events have ignited a larger discussion on consumers' expectations of data in society."

Brands like Facebook have traded on trust. Share. Be open. Allow us to access your computers and phones. You can trust us. Terms of service updates – no worries, simply accept. We are the good guys.

As part of deconstructing my Facebook engagement, I downloaded my Facebook "file". You can too.

It packages up the stuff you know you shared – photos, videos, messages, posts, even time-stamped events.

Read more: Ten things you should delete from your Facebook profile.

Sure, you expect that. What I wasn't expecting was to see a record of every contact on my phone.

Why? I don't recall ticking that box. It's not something they needed so I could post a picture of me walking the dog. And it was bang up to date, which means they must be constantly updating.

If they can grab my phone book – presumably by being connected through the app on the phone – what else might they – or others - decide would be useful?

Via many apps, and my smartphone, I've already accepted that my location is tracked, along with what I might be doing and who with. I've been cool with that, as most people seem to be, which is ironic as growing up in 70s Britain, the idea of ID cards was massively resisted. It's Orwellian, but okay in a benign society.

Does it matter? This is an interesting question. Do we want third parties sitting in other parts of the world with unfettered access to the behavioural data of New Zealanders?

In 2007, what became known as the "Anti Spam" Act was passed in New Zealand. This was designed to stop our email inboxes being filled with rubbish.

It was different, but similar in intent, to the UK's Data Protection Act of 1998, which is about to be superseded by a European Act, the GDPR, in May, which is heavily focused on data privacy and the rights of the individual.

The result of the Anti Spam Act meant many New Zealand firms had to recollect email permission as they hadn't been collecting email "ethically".

But as it was focused only on who they could stop in New Zealand, it didn't prevent overseas spam, just local, which generally wasn't the problem in the first place.

I've been working with data in New Zealand for nearly 20 years, predominantly through customer database marketing and loyalty programmes. Here, there is trust. There is corporate social responsibility.

Your supermarket is interested in what you buy, and might want to buy, not who you are going to vote for.

Ditto your credit card company, your sandwich shop, your department store, your pet shop, your petrol station. The New Zealand commercial data play is generally about being useful, helpful, and closing the loop on needs and wants.

But in the big bad world, it's clearly different and organisations who have projected a benign image, however wholesome in their core (Zuckerberg today described Facebook as "an idealistic company"), are clearly at risk of losing their way or allowing malicious third parties to take advantage of them, and their users.

Zuckerberg in front of US Senators today accepted that regulation was probably necessary and Facebook would play its part.

So, we need our governments to take protecting data seriously. We need a plan to protect our citizens (sometimes from themselves) from sharing their data in dangerous places.

But fundamentally, we need to have a voice with these overseas organisations who are increasingly playing such an important role in the daily life of New Zealanders.

We seem to be very concerned about foreigners buying property even when it's only a small fraction of property ownership, but apparently little around the potential abuse of the data of millions of Kiwis.

The Government's reported update of New Zealand data and privacy laws really can't come soon enough. Let's hope they consult well on them so they don't punitively disadvantage New Zealand businesses though.

Read more: Kiwi Facebook users caught between the devil and the deep blue sea.

In the meantime, what can you do as an individual? Think about the faceless overseas sites you share data with.

Think about the stupid quizzes that scrape your data. Make your own mind up about whether organisations like Facebook deserve your trust any more – I'd like to think they will earn back my trust.

But trust local retailers and organisations who have no agenda apart from being useful and understanding you.

- Ben Goodale is the managing director of justONE