Motivational reading: Clay Shirky's 'Here Comes Everybody'

I finally made the time to embark on Clay Shirky's book, which I've been wanting to read for months.  Having consistently come away from various blog posts and videos that he's shared a bit wiser than I was going in, I opened the volume with high expectations, which were met in the first few paragraphs.  His anecdotal example of the stolen phone, and his analysis of the extent to which it "demonstrates the ways in which the information we give off about ourselves, in photos and e-mails and MySpace pages and all the rest of it, has dramatically increased our social visibility and made it easier for us to find each other but also to be scrutinized in public," gets to at least one crux of our historical present.  What I like most in what I've read so far, however, is an unattibuted quotation that serves as a section header on page 6:  "Give me a place to stand and a lever long enough, and I will move the world."  For me, this stunning imperative provides a modicum of hope for the future, from the standpoint of a present that reads, all too often, as grim.  I recognize here the topos of the Archimedean point, but I can't recall the source of this "moving" (motivational?) citation.  Can anybody help me out? Clay, are you there? (You shouldn't be all that hard to find, right?)