Hostels are ideal places for individual travelers, families with kids and all kinds of groups (school, sports, organizations etc.)
Hostels are often a type of accommodation used by backpackers or young people who travel by impulse - going where they want, when they want taking advantage of the opportunities that comes their way, making their budget last as long as it is possible.
Hostels are less formal than other means of accommodations. The atmosphere is relaxed and you find facilities that guest may find friendships from all parts of the world. These facilities are guest kitchen, lounges, TV-rooms, laundry service room, bar etc.
The staff are local experts and gives useful tips to their guests. Sometimes they also arrange activities at the hostel or within the destination. As a guest, you have the choice to book at bed sharing room with other travelers or you may book your own private room.
It is also common for hostels to have information boards. These boards often show tips for what you could do at your destination, you may sign up for different activities, read about a staff favorite restaurant/pub or maybe post yourself at note asking for a travelling companion?