This is incredible. Population density down to a 5M resolution and they are releasing it for free. Governments can be using this info for everything from real estate development to better understanding census results.
Especially with the coming climate changes, the type of forecasting that we'll be able to do will be astounding.
Even for advertising and business planning, I could choose where I should put my next nightclub, advertisers can use it for campaign development and valuation. This is good info!
For those worried about privacy though, you should be. I've seen hackers find someone's apartment by using Google maps from a picture that shows outside, so Facebook using Aritifical Intelligence to identify buildings and areas (with images you gave them) does raise some interesting questions.
Imagine being able to look at a picture on Facebook of your significant other in a room...and have Facebook being able to tell you where that room is. If we're not there already...we will be.