Beginning January 1, 2016, the Royal Society (publisher of Philosophical Transactions and Proceedings of the Royal Society) will require the submitting author to provide an ORCID identifier as part of the manuscript submission process.
ORCID provides a unique identifier for all researchers that can be linked to their different research works and activities across multiple platforms. It also serves to distinguish authors with similar names and simplify searching of publications databases (such as PubMed, Scopus, etc.) to avoid retrieving articles by authors with similar names. Close to 1.8 million researchers have already created their ORCID iD. The service is non-profit and community driven. It takes less than a minute to register for an ORCID iD and it’s free of charge.
For more information, see the Royal Society’s blog post: https://blogs.royalsociety.org/publishing/from-january-youll-need-an-orcid/