It allows you to ask questions to people at a given place/location. ONLY people at this place/location will receive and answer your question.
1) Before you drive to see the band ask people at the concert if the band is any good.
2) Lost your dog in the park... ask people in the park if they have seen your dog.
3) Get the news from people that are there... i.e. ask people in Libya what they think of the war, people in Japan how the cleanup is progressing.
3) Want pics of the big game. Ask the people at the game to send them to you.
4) Ask the people on your favorite lake if the fish are biting.
The best way to get information about an area is from the people that are there... i.e. the locals....