Everything you post on it is marked with a location, or a place.
So anytime you wonder: what's that noise on the street ? Should I go to this gig, is it fun already ? Why is everyone talking about downtown Hong-Kong ? Well, just check it out ! Castr gives you a constant newsfeed of localized info.
You can follow the people that matter or the places where they matter; you can monitor whole cities or tiny villages.
But it's also a time machine. With the Mapsearch you can search anywhere in the world and know instantly what's going on there. Right now, or a year ago.
And, you know, it's free!