You thought no one was looking when you bought that package of Twinkie's last week, didn't you? Well, if you used a supermarket value card, that information is being stored in a database somewhere. Does it matter? Will anyone ever be able to look at the details of your diet? Perhaps not, but it still seems odd that supermarkets are so obsessed with tracking our purchases.

At first, value cards don't sound so bad. The supermarket gives you a card, and by using that card whenever you buy something, you receive a sale price reserved for preferred customers. But isn't that the same sale price that we all used to receive without a plastic card? Wouldn't it be easier just to give me the sale price automatically and forget about the plastic?

Apparently not. The supermarkets issue these cards so that they can study exactly what we buy, which begs the question: how bored do they have to be to study what I buy? I'm sorry, but I get the same thing every week, and rarely is it interesting. I half imagine a bunch of supermarket employees gathered around a computer: "Hey, look everyone! Joe just bought crackers again! The same exact brand as he always gets!" It pains me to think that someone could have a job that dull.

If the supermarkets want to know what products are selling well, can't they just check their inventory? Obviously, they wouldn't issue these cards if it there wasn't some benefit, but I don't understand how knowing my purchasing history can be at all helpful for them. Who knows? Maybe they're tracking how many times I use the checkout lane when I have more than ten items.

Supposedly, supermarkets use this information to mail special offers to their favorite customers, but, in my three years as a cardholder, I have never ever received a special offer from my supermarket. Apparently, I must not be one of their favorite customers. Just think. Without the value card, I would have never known this.

I guess I didn't mind so much when it was just supermarkets issuing the cards, but other stores have followed. Now, whenever I go into CVS, my local drug store, I am asked if I want a new "ExtraCare" card. I'm getting worried. Will every store I shop at now give me one of these cards? I hope not. I already have enough plastic in my wallet. I don't want any more.

Besides, drug stores offer a far more intimate line of products than any supermarket. That's the last store I want tracking my purchases. And, if I accept the card, will I suddenly feel obligated to buy more interesting items? Fewer Cheetoes, more condoms? Otherwise, what will they think of me?

I wish I had a solution to all this, but I don't.

Rip up my card? It's tempting, but why should I pay full price when everyone else is getting the sale price?

Shop somewhere else? That's hardly easy when just about every major supermarket uses these cards.

Or I could just do what so many already do -- sign up with a fake name. ("That's Bond, James Bond.... And could I have a TV Guide with that as well? Thanks.") At least, then your purchases can never be linked back to you. And, if we all do this, who knows what will happen? After all, once a store notices that the majority of its customers are named Elvis, they might just give up.

This piece originally appeared in the Sunday Boston Herald.