Well, technically they all have other 'stuff' to help you do whatever it is with that single box. Google is the only one that doesn't require you to signup befo

Well, technically they all have other 'stuff' to help you do whatever it is with that single box. Google is the only one that doesn't require you to signup before using it. Digg and HN kind of only have 1 input box. It definitely is an interesting trend. I've even tried to come up with startup ideas restricting myself to simple inputs like a single textbox. Sometimes adding some constraint helps you be more creative.