If you follow news related to HCI (human-computer interaction), then you probably saw multi-touch interaction demonstrations by Jeff Han. You probably already use (or played) with iPhone or iPod touch. So you know what multi-touch interaction is about. This kind of interface goes hand in hand with Subject-centric computing. Why?
Multi-touch interaction promotes direct manipulation with various kinds of objects. iPhone follows more traditional application-centric paradigm (with smooth integration of different applications). On the other hand, Jeff Han demonstrated almost application-less interface. Not only “documents”, but “things” that we are interested in can be surfaced through multi-touch interface. People, places, events, driving routes, songs can be represented as “subjects” in multi-touch interface and we can easily (naturally) interact with them. That is the way we would like to interact in subject-centric computing environment.
Multi-touch interface translates gesture-based interactions into operations on subjects (“things” that we are interested in). Subject-centric infrastructure can help to implement ‘glue’ that allows to identify and interconnect subjects “hosted” by various applications/services on desktops, intranets and the Internet.