If you're already wary of Big Data and the reach of the Silicon Valley tech giants, here's some more concerning news: Google might just know you better than your friends and family do.
To understand ourselves and the world, we turn increasingly to the dominant search engine. In doing so, we reveal a whole swathe of personal preferences that can be collected and analysed en masse.
That's exactly what Seth Stephens-Davidowitz has done.
A self-described internet data expert, he became fascinated with Google Trends, the site's freely available tool for judging the popularity of search terms, while completing a PhD in economics.
He later worked at the technology company, and his book Everybody Lies: What The Internet Can Tell Us About Who We Really Are looks at the "digital truth serum" that is internet search data.
"Certain online sources get people to admit things they would not admit anywhere else," he says.
While you might lie to someone asking survey questions to make yourself look better — what's called social desirability bias — your search history will reveal your true self.
The data Stephens-Davidowitz has gathered and presented in the book is particularly revealing on questions of intimacy. For example, the most common complaint about a marriage, Stephens-Davidowitz says, is not that it's loveless, but sexless.
"It easily beats the second complaint: the partner won't text me back," he told Lateline.
Stephens-Davidowitz believes Google search data may give a more accurate picture of homosexuality than a regular study ever could.
Surveys say about 2 to 3 per cent of American males are same-sex attracted; data from Facebook, where users self-report a sexual preference, is roughly the same.
But Stephens-Davidowitz says data he has collected from Google searches for gay pornography suggests the figure may be closer to 5 per cent.
"One consequence of my estimate is clear," he writes.
"An awful lot of men in the United States, particularly in intolerant states, are still in the closet.
"They don't reveal their sexual preferences on Facebook. They don't admit it on surveys. And, in many cases, they may even be married to women."
In fact, the most common way to end the Google search "is my husband ..." is with the word "gay", Stephens-Davidowitz says.
"It's about 10 per cent more common than 'is my husband cheating' and eight times more common than 'is my husband depressed', 'is my husband an alcoholic'," he says.
"It's the number one question."
Google data a study of human psyche, author says
So, in parsing the data — and there's a lot of it, given we make several billion searches a day, worldwide — what did the data expert find most surprising?
"The number of people making racist searches, looking for jokes mocking African-Americans," he says.
"I was disturbed how many people are making [those searches], in parts of the country where I wouldn't expect people to have the attitudes."
By that he means not just in the south, where the ghosts of slavery are most strongly felt, but in Democratic states north of the Mason-Dixon line.
Because we lie, every day, to others and even to ourselves, the kind of data Stephens-Davidowitz has analysed is hugely revealing, he says — and underutilised.
"Whatever field you're in, you can get quick insights in this," he says.
"Even if you are not a professional data scientist ... if you're just curious or in business, in marketing, there's so much information you can learn from Google searches, just very quick, to help you make decisions.
"I call Google searches the most important dataset ever collected on the human psyche. The more I study it, the more convinced I am of that."
