I would guess Google does more than just cookies. Most folks who have a router hooked to their cable modem (not sure about DSL) keep the same IP for months and months. I'll bet Google leverages this fact in an attempt to track you even if you delete your cookies.
mooching off the unsuspecting neighbors to get your self-satisfaction? For shame.
Thats nothing friend has a beta card (pre n) that is acctually 4 wifi cards in one nice compact usb houseing. It has a special software bundle that auto bridges any connections it finds in range. We too his laptop to local hot spot for open wifi aps. Conected to 4 diffrent ones had had well 2x roadrunner turbo (10mb cons 1 up)1 normal road runner cooking along at 6mb down 512 up and one of the better dsl packages at 5 down .75 up. Did a couple test downloads and got fairly insane speeds where it normally says like 500KB is said 1868KB. It really ment for large corps wich is how they are marketing it. This way if you need to go to another floor and loose a ap conection you are still conected to one or more likely with crappy connection but enough to not screw up a big transfer then pick up another one.
Id say if we ever see full blown muni wifi it will be damn popular for that. Drive around and your friend spouse or kids are playing their fave online game.
Mostly off topic but well isps selling data and google etc tracking you heh. When your spread out over 3 or 4 ips heh kind of screws things up for em dont it -- Evil does exist and it has a face to often that face is one that should look on their child with love in their eyes.