What are ARKs?
ARKs (Archival Resource Keys) are high-functioning identifiers that lead you to things and to descriptions of those things. For example, this ARK,
https://n2t.net/ark:/67531/metadc107835/
gets to a dissertation, and adding a '?' to the ARK gets you to its description:
https://n2t.net/ark:/67531/metadc107835/?
What's an identifier?
On the internet, an identifier is a URL, or part of a URL. For example, this basic ARK identifier,
is part of two different URLs (Uniform Resource Locators), also known as web links or web addresses:
https://gallica.bnf.fr/ark:/12148/btv1b8449691v/f29
https://n2t.net/ark:/12148/btv1b8449691v/f29
ARKs are especially good at being persistent identifiers.
What's a persistent identifier?
The average lifetime of a URL has been said to be 44 days. At the end of its life, a URL link breaks, which means it gives you the dreaded "404 Not Found" error. As irritating as it is – and most of us have seen it happen – it's a disaster for libraries, archives, museums, and other memory organizations. A persistent identifier (sometimes abbreviated to PID) is an identifier that in principle will continue to work far into the future, even as things move between websites. Normally when things move, we're burdened with broken links and having to learn to use their new URLs (links), and that's where identifier resolvers come in.
What's a resolver?
A resolver is a website that is especially good at forwarding incoming identifiers (those originally advertised to users) to whatever website is currently best suited to deal with it. To make this work, the hostname of the resolver itself should be carefully chosen so that it never has to be changed. Memory organizations, some of them centuries old, tend to have website hostnames that are especially stable and well suited to be resolvers. Other well-known resolvers include n2t.net, identifiers.org, doi.org, handle.net, and purl.org.
How do ARKs differ from DOIs, Handles, PURLs, and URNs?
These are all major kinds of persistent identifiers. The short answer is that ARKs are the the only mainstream, non-siloed, non-paywalled identifiers. Over 500 registered organizations have created an estimated 3.2 billion ARKs in the world, and no one has ever paid for the right to create them.
Would you be able to expand on that answer?
Superficially, these identifiers all have similar structure and purpose.
xxxxx
I've heard of ORCIDs and UUIDs – where do they fit in?
Those are special kinds of persistent identifiers. ORCIDs identify researchers, and they link to research works using ARKs, DOIs, etc. ORCIDs look like
https://orcid.org/0000-0001-7604-8041
UUIDs are globally unique, 37-character strings that are easy to generate but only become usable as web addresses when made part of a URL, ARK, DOI, etc, for example,
https://n2t.net/ark:/65665/3c2e39526-e0c3-41ae-be4f-07558a9458eb
