Hostels originated as places one could stay
at low cost by cleaning up after themselves
and exchanging 3-5 minutes of their time to
the up-keep of the hostel.
During the day while the hostellers are out and about
immersing themselves in the local culture,
or kicking back in the common areas writing email or letters home,
the sleeping areas are closed (but may be accessible with a key.)
Late night access is by key. Laundry, kitchen,
lockers and computer use is available. Trust
is the 'golden rule' among all the
hostellers. These customs are still observed
worldwide at most hostels, especially small ones.
There are many site on the web for reading about Hostels and Hosteling.
I would start with the great site called:
The Hostel Handbook has a good description about hostels it's also a great guide book.
The Hostel handbook.