They're also using the MAC address to identify the device, and I suspect from that to estimate the demographic: http://new.pitchengine.com/pitches/60f7865a-f3ac-4167-920c-5...
This seems to be echoed by some legal people: http://www.huntonprivacyblog.com/2011/05/articles/article-29...
> Unique identifiers (such as MAC addresses) should only be stored for a maximum period of 24 hours, and should subsequently be deleted or anonymized.
And they have an opt-out page: http://www.presenceorb.com/optout.aspx
But how many people would opt-out of something they didn't know was tracking them?