Reading has always had a social dimension, but the promise of new reading services lies in something we don't yet have a name for.
We're told that services like Findings and Readmill "make reading social." Both sites encourage members to post quotations from what they're reading to share with other members. They're similar in purpose, though Readmill places its chief emphasis on books -- and is heavily invested in the iPad as a reading platform -- while Findings feels more browser-centric and encourages its users to clip from online text of all kinds. So do these sites "make reading social"? Well, it depends on what you mean by "reading" and what you mean by "social."
If we define reading relatively narrowly, as what happens when our eyes are actually moving across a page, then social reading only would happen when you're looking at a book that someone else had read and annotated before you, so that you were encountering that reader's responses as you were encountering the book itself. (Amazon allows Kindle readers to view passages in a book that others have underlined, which is the digital version of this experience.)
Of course, if having a book read to you is "reading a book" -- which it surely is -- then that kind of reading is intrinsically social ... but is it less social when a father is reading to his daughter in her bedroom than when, say, an author is reading from her new book to three hundred people in an auditorium? Or more so? Or, and here's the right answer, social in a very different way, such that the word "social" is manifestly inadequate.