<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">
Peter,<div><div><br class="Apple-interchange-newline"><blockquote type="cite"><p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Helvetica" size="3" style="font: 12.0px Helvetica">Once I have account linked to a plaxo account (as introduced by an openid positive assertion), I have no expectation personally that the OP is further involved in those matters of contractual privity between me and plaxo. Sorry, OpenID OP: you are not a PKI style governance model controlling "use" of the identity and associated attributes by the relying party. This is especially true in the account linking model that almost all the major RPs use (which contrasts with Nate's Shibboleth SSO model, incidentally).</font></p> </blockquote></div><br></div><div>It contrasts with our major prevailing *trust* model, where we do indeed recommend that SP's discard of all attributes they've received once they no longer need them. This is to prevent duplication of data, which leads to stale information, confusion over who's authoritative within an organization, and many points at which user privacy can leak out. There've been enough articles about "6 million yaddity numbers lost by blah" that nobody wants to headline another one of them.</div><div><br></div><div>In practice, there are a lot of applications that keep attributes for a long time to persist a remote representation of a user. Our learning management systems and the implementation of Shibboleth in Microsoft DreamSpark alongside LiveID are two good examples.</div><div><br></div><div>I consider this an art, not a science. Centralize all the data it makes sense to centralize: it needs to be commonly used and useful. For the rest of it, and for applications that can't use centralized data, keep it with the app.</div><div><br></div><div>Take care,</div><div>Nate.</div></body></html>