Keeping track of the identity of individual researchers across global information systems presents many challenges. A researcher may use different variations of their name; several researchers may have the same name; confusion arises when a researcher moves from one institution to another; an institution may even have the same researcher listed more than once in their own records. Similar problems emerge with groups of researchers. To allow the discovery of research datasets that share a common researcher or research group, a common public identifier is needed for referencing. A researcher ID is a unique identifier which you can add to anything which define you as a researcher: papers, blogs, published datasets, web-pages, code repositories etc. It will help other researchers to identify you more easily and it will make it easier to discover any aspect of your work.
How to get one
There are several providers for researcher-ID, the ANDS guide on identifying researchers is a good place to start to get more information, so you can choose which is the best option for you. If you do not have particular requirements ANDS is advising to use ORCID, an open, non-profit, community based initiative. ANDS is trying to get the ARC to allow use of orcid identifiers in grant submissions. This means that the reviewers of an ARC grant proposal might be able in the future to use the researcher orcid to have a full account of a their work output, including production of datasets and code, which are now often overlooked. If you have more than one researcher ID you can often link them together, though it is easier to manage only one. On the ANDS website you can find lots of resources including a variety of videos showing how a researcher ID works and why is important to have one.