I should clarify that I don't see technological implications as central themes in IJ, but I do find it really intriguing that rather than excluding or hand-waving issues that have to do with technology he dives in and gives them what seems to me a great deal of good, hard thought.
The book hit me really hard emotionally as well, and for me a lot of the anxiety centered around how fragile our assumptions are with regards to communication. All of DFW's exhibits to me a neurotic fixation with the other person understanding exactly what you mean (compact history of Infinity especially, where the book reads differently depending on how comfortable you are with exploring some of the proofs and concepts involved, you could skip the I.Y.I's and still get a really strong and interesting book, but the experience would be different), and it is a lot of that anxiety that hit me hard.
It just seemed interesting to me that technology and media fit so well with that central emotional point. If we can't even communicate to people in writing or speech, mass communication could fare not better.
It's sort of like talking about all of the AA reference in the book. As a topic there are a lot of things you can say about addiction and rationalization and human ritual, but AA was just a handy analogy to talk about all of that stuff, and more importantly to evoke certain feelings in the reader.
It's easier to talk about the set pieces of the book than it is to try and clearly articulate how it makes me feel, is all.