I make some contributions to Swedish wikipedia. I have hardly used WikiData at all, and frankly I find it overwhelming and maybe not so intuitive, but have made some very minor contributions and modifications. I realize that I have made a number of contributions indirectly, e.g. through creating inter-wiki-links via the wikipedia interface, or entering VIAF ID:s which later have been picked up by bots and entered into WikiData.
Please let me know if any of my contributions (directly or indirectly) simply are wrong or in any way improper, misleading or confusing.