Who is the greatest modern-day thinker?

Stephen Dubner asks, his readers answer.  I say dead people don’t count and give your answers in the comments.  Can I consider Tim Berners-Lee for my nomination or Marc Andreessen — you used a browser to read this post — or whichever single person is most responsible for Google or search more generally?  I don’t intend any slight to Richard Dawkins or the others but I just don’t see how they stand up to these guys.

Addendum: Arnold Kling nominates Vinton Cerf.