I've followed the microsatellite/nanosatellite industry for a long time, and these people are impressing the heck out of me. First, there's the technology of putting imagers that can pick out individual trees into 3U CubeSats (satellites built of three 10cm-square CubeSat buses). Second, for their vision of changing the world. Third, because of the quiet way they went about putting the pieces in place: hardly anyone even noticed when they flew their two test satellites.
Having frequently refreshed imagery of most of the globe available at low cost at the click of a mouse is going to be very, very interesting. This service and others like SkyBox are going to make everyone in the world the equivalent of a mini-intelligence agency. Scientific, environmental, commercial, military... I don't think anyone, not even the Planet Labs geniuses, knows all the applications this will be put to.