Both the eBw 1150 and the iLiad have input screens. The 1150 is a touch screen, whereas the iLiad is Wacom (requiring a specific stylus). Most PDAs have touch screens. Probably he's primarily thinking of the iPhone here.
As far as social networking goes, I guess we have a lot of solitary readers here, but some people really enjoy discussing books with others. There are quite a few email lists out there devoted to specific authors or books, as well as discussion boards on websites. I participate in three myself. A way to set up reader discussion groups via the Kindle could be extremely popular, for example, with those who belong to reading clubs or who read the "Oprah" picks. I don't know if this is what Scoble had in mind or not, but I don't think it's that strange a suggestion.