The solution that discloses the least amount of identifying information and best limits its use is the most stable long-term solution. One of the tenants of the "Laws of Identity" is minimal disclosure; so why are people ignoring this when they implement Information Cards? There are a three main uses (in my mind) for Information Cards; "form filling" (email address, name, etc.), authentication and authorisation via claims; all important as I try to write the last bit of SharpSTS and start to issue my own demonstration cards. These are separate functions in most web sites, form filling is used...