danah boyd's latest post on Many-2-Many is called contextualizing a social network website, which I first came across quoted and commented on in Marc Canter's Facets of your digital lifestyle, and also saw posted on danah's own zephoria blog.

As always, danah's post makes excellent points. At the end, she adds: "Note to FOAF folks: build in faceting, please", and Dan Brickley's considered response is one that follows danah's post.

I think the thing about identity, that is often being skirted around in online identity discussions, is what in meatspace we usually call the body, or the body-mind. Without getting too metaphysical about the web / online body discussion, I think there are practical features of individual online identity that are being shackled to online spaces (sites, networks) because they can't yet be attached to a full-enough equivalent of individual bodies online.

Social network sites, and other online networks like IRC and IM, in which we have some unique identifier and potentially profile information, work to give each person various parts of an online body within the space of their network.

For example, I regularly hang-out in Joi Ito's IRC chatroom #joiito, and use the nickname "JayF". Joi's chat robot, JiBot, records some attributes about me that JiBot displays when I join the chat. Within #joiito, my unique identifier is my nickname, and JiBot holds my profile.

On the Internet as a whole, outside of any particular site / network, there is no full equivalent of a body to which to give identity. I think that such a full-enough equivalent includes not only unique identifiers and personal profile attributes, but is contextualized by its relationship to other people, places and things— including its present-time presence (e.g., location, profile facets expressed) in that sphere of relations.

Email, which can in some ways be used to uniquely identify people, doesn't have such presence. IRC and IM add online presence to unique identifiers, but, like email, don't offer any extensible means of expressing profile attributes (including relationships to others, except in IM's private contact/buddy lists).

FOAF offers an extensible means of expressing profile attributes, including some ways to both uniquely identify people and to express relationships between people, places, and things. But, FOAF is more a file format than a network, and so can not be in itself either the means of identity or of presence. (In other words, something outside of FOAF has to point to FOAF files.)

While I think there a number of good things that can come out of making all of these pieces more interoperable, I think the core element is making identity (i.e., having an online body) a feature of the Internet itself—in other words, specifically a general network service.

I believe that the closest model to this is actually DNS. DNS is an identity service for network server services—it basically gives server services ambulatory bodies on the Internet.

DNS essentially provides the infrastructure for uniquely identifying, basically profiling, and registering the presence of server services. In this context, I see presence as meaning IP address, and profile as being the relation between IP addresses and domain names.

So, what I see as missing is a network services that gives personal identifier and profiles ambulatory bodies on the Internet. That service can (and, I think, ideally would) utilize a file format like FOAF to express profiles. It also can use protocols like Jabber (XMPP) to express a real-time aspect of presence.

I also imagine then that this kind of service can be built-into websites and web browsers, as well as be part of the evolution of email. For example, when you visit a website, your browser could lookup that site's "presence interface" and then upload your (default or a custom) profile—not simply indicating that you are "logged in", but that you connected and interacted with the site.

These interactions should not only log on the site, but also become part of your identity profile itself. Each interaction potentially modifies and exercises the facets of your identity and the dynamics of your relationships / social network connections. You aren't simply Mr. Website-Reader, you are Mr. Website-Reader-who-read-icite.net/blog-at-. . .

There is more to this even, as your identity isn't wholly owned and controlled by you. So, other's can assign attributes to you based on their relationships to you. For example, RageBoy is infamously working to attach an online attribute on someone else.

I think FOAF has a lot of potential for storing attributes of all kinds. And, with multiple FOAF files (or multiple restricted views of a single FOAF file) about a person, different files / views can potentially express different facets of identity, for oneself and also for one's relationships with others.

But, I think what needs to be done as well is to create a network (decentralized, scalable, largely p2p) service through which these profiles are like ambulatory bodies—they move and pass through different sites, in each expressing different facets, yet without becoming fragmented and riddled with artifacts through lossy duplication.

(Note: just saw the also related comments from Jeremy Allaire and more comments from Marc Canter in Marc's Good Start post.)