how does this data get used to track your location?

while walking around with your ‘smart’ phone in your pocket, unless configured otherwise, it will be scanning for wlan broadcasts. the geolocation of those broadcasts are known (either other users’ devices configured to provide that data to say google or via google’s streetview missions) and thus your location can be known.

that your ap at home is called “dd-wrt” is not such a big deal as far as tracking your location. it also provides its mac, which unless configured otherwise, is unique.
that your phone/laptop/… detected wlan access points with macA macB, then macB and macC but no longer macA, your location and direction can be extrapolated.

is that not the issue?

First, this isn’t a breach of privacy, but a breach of trust. Big difference. Second, it seems everyone is getting very relaxed on what data Google has about you. I suppose it will be okay if Google knows your financial institution’s account number and SSN, yes? Lastly, Google has been tracking this data for some time, not just starting. I was never aware of this. What else about me are they tracking? My daily commute to work? What I have for breakfast each morning? I don’t know, because they don’t say.

Breach of trust.

Are you a home owner, Aaron? Do you constantly get junk mail about refinancing your home loan?

THE GOVERNMENT IS TRACKING YOUR PHYSICAL LOCATION, AND ALLOWING PRIVATE COMPANIES AND INDIVIDUALS TO DO SO AS WELL!!!

AAAAAAAAAUUUUUUUUUUUUUUUUUUUUUUUUUUGGGGGGHHHHHHHHHHHH!!!!!!

Seriously, what in the world are you even going on about? Your router doesn’t even move and I guarantee you it’s already listed in at least 10 location databases, if not 10 times that number.

Honestly. Freak out about the fact that nefarious individuals will track, and sell, information about *_nomap locations explicitly. But this Google decision? What a joke.

Google’s “Do No Evil” died years ago. P.S. Are you an Android user?

Let’s say you’re this person with a megaphone and a soap box. Every morning you’d come out of your house, go to the edge of your front lawn next to the sidewalk and stand on your soapbox. With your loudest voice you would yell out through the megaphone “THE END IS NEAR!” over and over again, until night falls and you’ve mostly lost your voice. You repeat this day after day.

The town you live in is small, you have neighbors who hear you every day. They tell their friends, and their friends of friends. Eventually everyone in the town knows about you. You, your soapbox, yelling through a megaphone is common knowledge.

After months of your yelling regiment, a out of town traveler passes through looking to visit a friend of theirs who happens to live in your neighborhood. This person stops at a convenience store and asks for directions. The clerk draws this person a map, along with a stick figure that looks similar to someone holding a megaphone on top of a soap box, and tells the traveler to make a right turn at the loud obnoxious guy.

How does privacy work here? You could complain to the clerk to not use your performance as a land mark, but the clerk responds pointing out that you’re doing it in public and you argue for a while about how it’s still within the confines of your property, clerk again responds with the rest of the town knows about it. You go to a town meeting and demand that no one even acknowledge that you exist while on your megaphone banter. The towns folk respond with a request that if you must do it in public you have to append your announcement with a disclaimer.

802.11 can be really loud by nature, it’s everywhere here in San Francisco. I can stand in the middle of my street and see/hear about three dozen different ESSIDs, just as I could also hear my goth/metal down stairs neighbors having a party, or the kid across the street practicing his trombone, or the couple one over having a fight. Private sounds waves carry over into public a space aren’t really all that private anymore, especially if it’s going on 24/7, like the whirl of a fan part of a hydroponic system not really all that well insulated.

I help run a hacker space here called Noisebridge, it’s a non-profit public space/community for people to come and use tools and create interesting things, also to hang out. The space is rather large and we offer free internet (when it mostly works). Several of us, including me, have a very strong stance against implementing anything in the space that would log or track individuals coming in/out. Short logs or no logs on our servers, no neat tool to notify our IRC channel that certain MAC addresses are in the space (though that has been a fun opt-in idea), and no security/web cams (as much as things get stolen all the time). Whenever I bring a friend into the space I warn them that even though we have such a strong stance on privacy and no tracking or surveillance, it’s still very much a public space and the wifi/network are very much open to all to sit on and do/sniff whatever they want, if privacy is what they’re looking for they should leave and go to some place private, or wear a mask and make sure they tunnel all their traffic through Tor (quick plug for http://noisetor.net ) while using our network.

By owning a cell phone you’ve opted into telcos and government agencies tracking where you go and when, no way to opt out other than to not have a cell phone. Might as well give permission for a 3rd party to do something interesting with that data (Google Latitude for instance). By running a radio transmitter in your home, you’re effectively opting into others hearing you (man times miles away). I feel that a larger group might as well do something interesting with knowing that information as well. I do think it’s silly that Google says you can opt out by having a disclaimer on the end of your ESSID, but it isn’t as silly as requiring everyone to ignore radio waves permuting past your homes walls and property line into public space to remain private unless otherwise stated so.

If you don’t want people to know where your access point lives, I would suggest painting your walls with lead paint, much in the same how I would also recommend to folks who want to be private, please don’t have sex on the balcony once an hour on the hour, or please don’t be that guy with a megaphone demanding that no one notice him or her.