Re #2: it already happens, just in a limited capacity. A lot of mobile ad networks (if in app, not mobile web) will cookie you with the UDID before and after y

Re #2: it already happens, just in a limited capacity. A lot of mobile ad networks (if in app, not mobile web) will cookie you with the UDID before and after you click on a link. Android lets you pass some referral information on links to the Google Play market, letting advertisers do this w/o cookies and also on the mobile web.