Conceptually the portable e-Ink reading experience for me includes the following features:
1. Loose ends: in my undergrad days at U-Michigan when I wanted to find something I went to the library, since my personal collection was very limited. And when I wanted to go back to confirm something, I had a physical/spatial memory of it (book X and top-right page position, for example). Now there are so many forms that text, let alone other media, can take that my ability to remember is hampered: was it something I got from a podcast, youtube, blog, NPR story or monograph. By corralling some of the text-base content to my kindle or PC/browser bookmark, I know where to go to find something.
2. Amplified reading experience: I have grown fond of the ability to lookup people, places, and things in the middle of my reading experience. And the ability to adjust font size (bigger at night when my eyes are tired or in situations where light is poor) and to make annotations, and to be reading a dozen items concurrently all add to the volume, variety and quality of my reading life.
3. Opportunistic reading: I read in smaller increments in addition to my pre-digital habits of sitting down for 30 minutes or more for serious pieces. In other words, my eReader lets me switch on, go the the last page read and begin straight away; on the spot, at the spur of the moment, as I wait for one thing or another during my day.
4. Helpful extension to my PC screen: being able to grab things mid-stream as I surf through websites, articles and emails and to transfer these onto my eReader is great. I can read later. Anything longer than a screenful, or anything denser than casual writing works best on paper or e-Ink for me. In addition, I can mark up. I can repost to FB or Twitter (although I'm not used to that feature, really). I can view "popular highlighting" for some titles (a rough and ready way to see salient passages from other readers' markup). I can copy/paste my annotations to give to others via printout or email, etc.
5. Instant gratification: Being able to hear an author on the radio, catch it in print or online, or seeing it on TV used to motivate me to look up the book and consider purchase or borrowing. Now the ability to download a sample chapter without delay feels like magic (powerful, useful and effortless).
6. Portable brain: Being able to look up something out of thin air (wirelessly) is reasonably efficient and being able to carry around reference materials (manuals, instructions, baseline records, etc) is convenient, too. Much like the story of the person with just a hammer in the toolbox who viewed the world in terms of nails to be hammered down or pulled out, the person with just a few intellectual tools and accoutrements sees the world in those terms. But with the Internet and other reference materials at hand, one's range of tools expands greatly and grows daily.
7. Always on: subscriptions (free or paid) are delivered wirelessly, giving the experience of immediately being up to date.