There is no point in arguing that it isn't scary because lots and lots of people are convinced it is scary. Dan Tynan for example, is either scared himself or convinced that he can scare enough people to attract lots of readers to his scary article about data mining.
First of all, we need to be clear about what data mining isn't. It isn't about a billboard suddenly appearing saying, Catherine spent 45 minutes watching videos at I Feel Myself yesterday. (For those who don't already know, I Feel Myself is a porn site that features amateur videos of women getting personal with themselves that attracts significantly more women than other porn sites.) That would be a legitimate fear but that isn't it.
No data mining is all about collecting all sorts of data about what people purchase and then using that data to frame the way companies present their products and services. In some ways it ought to be reassuring. The company presenting options to you doesn't need to know your name, your address, your sex or anything else to make the connections.
The problem goes the other way. Give a data miner your credit card history for the past two or three days and they can tell whether you are a man or a woman, approximately how old you are, how much education you have and what kind of neighbourhood you live in. And that is kind of intimidating. Suppose Karen goes out and buys a Jane Austen novel, some tea, some fluffy slippers, some knitting supplies and goes home and makes the tea, puts on her fluffy slippers and starts alternatively reading a few pages and then knitting awhile and she is just loving this when her phone goes and she looks to see a text message saying, "We think you may enjoy visiting I Feel Myself."
And the really scary thing is not if they are wrong. That would just be irritating. The really scary thing is if the pitch is right. It's really scary to think that someone could figure out something that intimate about you just from fluffy slippers!
But should it be?
I'm sure you can decide for yourself but you might want to start your considerations with this question: "Who do I think I'm fooling?" Do you really think that your intimate self is this locked box that no one else can see unless you let them see?