Ebooks meet social networking
I ended up buying a Kindle recently because of a particularly long trip to the east coast of the US. I started printing out books for airplane reading a while ago and found that it worked fairly well. You can get all sorts of classic books for free at places like Project Gutenberg or Munseys, and what I'd so was print a book and then tear off and throw away the pages as I read them. For a trip from California to New York and back this works just fine, but if you're on a much longer trip then the pile of books that you're going to eventually throw away gets annoyingly big and because of this I picked up a Kindle.
Once I had a Kindle I downloaded a few ebooks for it. I first tried the free ones that you can get from Amazon.com, but it turns out that those try to combine books with social networking. In particular, these ebooks show passages that others have marked as being notable, sort of a version of highlighter for an ebook. I found the combination extremely annoying and quickly moved on to other sources for free ebooks.
I found ebooks to be very useful and found the Kindle to be well worth its price, but the combination with social networking just didn't work for me.