http://online.wsj.com/article/SB10001424052748704679204575646704100959546.html Race Is On to 'Fingerprint' Phones, PCs
This is not good at all This type of thing should really be illegal to do. I wonder how he would like it if I started stalking him and making a file on his whole life and then put it up for auction to the highest bidder.
But they are going to do it anyway, if they haven't already. Especially phones. Wi-fi is kinda dangerous if you think about it.
Cookies have legitimate (in fact, mostly legitimate) uses: they allow websites to maintain the concept of a "session" by persisting state data across consecutive requests from the same client. You can do it without them, but alternative methods can't generally allow automatic log-ins. Fingerprints... don't. They're inherently statistical in nature, and you can't take chances that the guy accessing the website currently is the same one that did a week ago if there are so many instances where they can't generate a usable fingerprint. All they become useful for is tracking those that you can track ... and with policies like "we keep this data for the foreseeable future" and no opt-outs, that's basically an invasion of privacy. Google and Facebook have had some major blow-ups with authorities over much less questionable practices.