ORCID = Open Researcher and Contributor ID. Free registration of nonproprietary name code for contributor / author identification. ORCID launched its registry services in 2012, and started issuing user identifiers
Register for an ORCID ID.
The aim of ORCID is to aid "the transition from science to e-Science, wherein scholarly publications can be mined to spot links and ideas hidden in the ever-growing volume of scholarly literature". Can be used to provide each researcher with "a constantly updated ‘digital curriculum vitae’ providing a picture of his or her contributions to science going far beyond the simple publication list."
It has been noted in an editorial in Nature that ORCID, in addition to tagging the contributions that scientists make to papers, "could also be assigned to data sets they helped to generate, comments on their colleagues’ blog posts or unpublished draft papers, edits of Wikipedia entries and much else besides."
What is a digital object identifier, or DOI?
A DOI is a unique alphanumeric string assigned by a registration agency (the International DOI Foundation) to identify content and provide a persistent link to its location on the Internet. The publisher assigns a DOI when your article is published and made available electronically.
All DOI numbers begin with a 10 and contain a prefix and a suffix separated by a slash. The prefix is a unique number of four or more digits assigned to organizations; the suffix is assigned by the publisher and was designed to be flexible with publisher identification standards.
We recommend that when DOIs are available, you include them for both print and electronic sources. The DOI is typically located on the first page of the electronic journal article, near the copyright notice. The DOI can also be found on the database landing page for the article.
(Source: APA Style website)