I remember when I got my first book from Amazon several years ago. With it came an Amazon bookmark and for the first time I had something tangible from the internet. The book could have been from anywhere, and the clever packaging got thrown away, but the bookmark meant that I had some evidence of the virtual world I'd been exploring.
It's happened again now. I've got a galley proof copy of a book that I've followed as it's been drafted in public. I've been reading the blog of one of the authors, Robert Scoble, for a while now, and here is something tangible of his existence.