I'm as patriotic as the next guy, but in a couple of ways I'm positively un-American. For example, I've never set foot inside a Wal-Mart, never eaten a McDonald's hamburger, and never signed up for any supermarket's "club card." The first is because I believe big-box stores are destroying small-town America's main-street shops, and the second is because I'm a snooty foodie. My recalcitrance to add my shopping habits to some corporate database, however, is more complicated - but it's based on the simple fact that I'm a privacy junkie. Unfortunately, it's about to get a lot harder for me to keep my personal information personal.

Why? Because of an acronym that's rapidly worming its intrusive way into all of our daily lives: RFID. Short for radio-frequency identification, RFID systems include a tiny transponder that can be embedded into ... well ... practically anything, and a sensor that can read the information carried by that transponder. The information encoded in RFID transponders can be read passively, meaning that if you have one embedded in your MasterCard, for example, all the information stored in it can be read without you even knowing that it has been accessed. These "no-swipe" credit cards may radically increase the possibility of identity theft, raising the ire of observers such as Senator Charles Schumer of the Senate Banking Committee.

What rankles privacy advocates such as myself are the more Orwellian aspects of RFID technology, such as the fact that they can be used quite effectively as location trackers. A recent CNET article about the Department of Homeland Security's Real ID program reports that "A radio frequency identification (RFID) tag is under consideration." With an RFID-enabled Real ID card in your possession, strategically placed sensors could track your every move. Now, call me paranoid (if you haven't done so already...), but I'd rather not have Big Brother keeping an eye on my peregrinations.

How tiny can RFID transponders be? A couple of weeks ago, Hitachi unveiled a prototype of an RFID chip that's a mere 0.05 by 0.05 millimeters - think talcum-powder-size - and that can store and transmit a 38-digit I.D. number. The truly paranoid (raise your hands, now) can imagine anti-government protestors being "dusted" by these micro RFIDs and tracked at leisure. I'm certainly not implying that such skullduggery will happen - I'm just saying that it can happen.

RFIDs certainly have their legitimate uses - inventory-tracking, for example - but even the most innocuous uses have their trade-offs. For example, many states have an RFID-based drive-through toll-paying system for bridges and turnpikes - here in California it's called FasTrack. Thanks to my far-less-uptight-than-me wife, we have a FasTrack transponder on our Mini Cooper - and now some database somewhere knows that I visited my folks across the San Mateo bridge last Saturday, then drove back across the Dumbarton Bridge to catch my daughter's rugby game at Stanford. I can come up with no reasonable reason as to why my comings and goings being monitored should give me pause, but I'm willing to admit - albeit sheepishly - that it does.

That's the problem with being a privacy junkie - you can feel mighty silly sometimes.

But still...