Anyway, in my research I think I have found three ways that mobile usage is unique from other media technology. I'd love to get some feedback (hopefully in time to incorporate into my paper!) on these, so I thought I'd share them here.
1) Ubiquity of access
Mobiles allow and encourage always-on, anywhere and anytime access.
Repercussions: nomadic information access; attention deficit; information capture to read later; changing sense of personal, work, and social spaces
Needs: speed of access; atomized content; file syncing and version control
Innovations: cloud computing; proactive search; automated metadata
2) Unique design
Mobile devices not only entail smaller screens than PCs but also have a variety of (smaller) input mechanisms (touch screen, trackball, keyboards, etc.) modalities (text, speech, photography, video) and platforms .
Repercussions: multi-platform support
Needs: small scale design; multimedia content; touch screen input; limited user input (based on difficulty in entering large amounts of text)
Innovations: QR Codes; automated linking and integration with native applications; actions based on various input methods, e.g. user shaking device (iPhone); clustered browsing
3) Contextual awarenessMobile devices are aware of a user's time and location and as mobiles tend to be single-user devices can draw upon automated or supplied profile data. The aspect most unique to mobile devices is the ability to determine a user's geographic location.
Repercussions: participatory surveillance; privacy concerns; geographic relevance
Needs: geotagged resources, GPS; precise location determination; widespread network access (incl. basements, rural, etc.)
Innovations: location-based applications and advertising; location sensitive maps and wayfinding aids; augmented reality; personalized content