Wikidata - the backbone of Wikipedia
Wikidata is a collaboratively edited knowledge base operated by the Wikimedia Foundation. It is intended to provide a common source of data which can be used by Wikimedia projects such as Wikipedia, and by anyone else, under a public domain licence. This is similar to the way Wikimedia Commons provides storage for media files and access to those files for all Wikimedia projects, and which are also freely available for reuse. Wikidata is powered by the software Wikibase.
An intro to Wikipedia
Database schema of Wikipedia
how to/ not to contribute to Wikidata.
Rahman - Wikipedian. Sysop at Telugu Wikipedia and Wikisource. contributor