Here are some quotes from reddit, in the event your mac is stolen:
"The mac address can be used to locate the machine if you happen to be a college student, or there is a large subnet you suspect the computer may be used on locally. http://learnlinux.tsf.org.za/courses/build/net-admin/ch03s05.html
arp -a will get you the location of your computer on a subnet. It is harder if you don't have that edge, since mac addresses are often completely obfuscated behind a router (the data link layer will use the router's mac outside the subnet). Do you use something like "foxmarks" that sinchronizes your firefox bookmarks or something like that? You might be able to get in touch with an admin at a site like that to get some access to their server logs.
Your best bet, really, is the serial number (which can't be spoofed or swapped out with a new ethernet card). Take it down to the local pawn shops, and second hand computer shops, and see if you can find the fence (just look at all the macbooks they are selling, don't let the shopkeeper know what you are doing or you will be kicked out)."
"Pawn shops have 1 week windows where they have to hold an item and cannot sell it (sometimes this is more "in theory" than what they follow to the T).
Honestly, you should report this stuff to the police because they check the pawn shops for you when you report stuff missing and can give the MAC address to all the pawn shops anyway."
"with said Serial and particularly MAC address, your laptop can easily be tracked as soon as said douchebag connects to the internet.
its just a matter of incentive for either Apple or the law enforcements. in order to arouse Apple's interests in recovering your beloved MacBook, you would have to be a major movie star with dashing good looks, a car to match and numerous woman friends all suggestive of extremely good breeding quality with pics to prove it.
in order to arouse the law enforcement's interests, you would either have to be a major drug dealer known never to take sunglasses off, a terrorist or a pirate. what would happen at the start is, the fat NSA man in the know will get a detective or agent on the phone, one that knows how to string numbers together and what GPS is, he will then call in a ticket to a state or federal agency with a cyber crime unit, who would in turn call in the local police department or sheriff to said douchebag's location, which if house will need a warrant for bashing into for confiscation of evidence, then to be passed onto forensics for identification and verification, and then to the docket tightly sealed in an evidence bag if douche denies anything.
so you see, you're a nobody to Apple but another returning customer, so either go get busy lookin for chronic somewhere, or go to Hollywood and apply for some auditions, you might make it big, or attend some kinda radical Madrasa in Mecca ...or just buy another laptop.
edit: on a serious note, i do feel for you. i know that if this happened to me in the UK, i would not cease bother apple and the police. the process by which they would track the device is incredibly simple if the douche has a more or less stable network, only corporate greed and red tape will make it complicated. carry on calling Apple, do not stop, and find the phone number for your State Police Dep's Cyber Crime unit, yes, there is such a unit not matter what they tell you, they will try to shield the number at every cost, perform every trick in the telemarketers' book to get through to them, someone there will be of some help. If they don't help, get a lawyer, because it is their duty."