Identity and Presence

I was reading an interesting post by Alec Saunders who was inturn commenting on a discussion about presence management. The title of the post intrigued me "Unifying Presence on the Desktop" if only because it seems that the desktop is the last place we should be unifying presence. If anything our mobile phones are the more logical place to control presence. Ideally presence management is a service that we want based in the "Cloud". ie. on the Web. We need an open interface that allows our VOIP service, our IM services and our mobile phone operator to interface with our presence manager. The cloud-based service, because it is always-on can make contextual deductions about our presence. What do I mean by that? Well if our presence manager is integrated with our calendar it can determine whether we are in a planned meeting and hence less likely to want to be distrubed by a voice call. Instant Messaging systems should be able to identify if we are at our usual desktop or laptop, or accessing via our mobile phone's IM platform. This information when coupled with knowledge of past behaviors can increasingly make active decisions about our status and what level of accessibility to provide to family, friends, co-workers, bosses and other contacts.