Wikidata is a free knowledge base that you can edit! It can be read and edited by humans and machines alike, and you can help. Go to any item page now and add to this ever-growing database!
Need some help getting started? Here are some pages you can familarise yourself with:
Wikidata:Tools - A collection of user-developed JS tools to allow for easier completion of some tasks.
If you have any questions, please ask me on my talk page. If you want to try out editing, you can use the sandbox to try. Once again, welcome, and I hope you quickly feel comfortable here, and become an active editor for Wikidata.