An ARK provides extra services above and beyond that of an ordinary URL. Instead of connecting to one thing, an ARK should connect to three things:
- the object itself,
- a brief metadata record if you append a single question mark to the ARK, and
- a maintenance commitment from the current server when you append two question marks.
In a web browser, for example, if you enter
it returns a brief machine- and eye-readable metadata record, such as
erc: who: (:unav) unavailable what: Truckee River, below Truckee Station, looking towards Eastern Summit. -- Photographer's number: 222 -- Photographer's series: Central Pacific Railroad, California. when: (:unav) unavailable where: http://ark.cdlib.org/ark:/13030/tf5p30086k
It is a side-benefit of ARKs that an object's metadata doesn't need an identifier different from that for the object, which cuts in half the number of identifiers that need to be generated and managed.