A very interesting story that does not seem to make the big headlines despite its crucial importance in my view.
Google Street View, already criticised for other reasons, all linked to privacy, acknowledged that it takes the Wi-Fi details of people, i.e. their MAC addresses, that will be able to any user using location-based services. In other words, your neighbour or your potential hacker can know all about your Wi-fi, making easier to hack into your computer.
A "bemol" though: if you have configured your Wi-Fi device not to broadcast, the signal and information should not be available. Another reason to do it, if you have not already done so.
"Google explains why Street View cars record Wi-Fi data"
when we know that Google will have 96 pc of the UK roads on it: "Google Street View to cover 96pc of UK roads"
For a general view of privacy issues Google services raise, see the letter addressed to the company ten European authorities in charge of protecting IT users privacy, CNIL, press release 20 April 2010. See also (in French), "Les gardiens de la vie privée exhortent Google à respecter les lois" (Depeches du Juris-Classeur, 23 April 2010)