Theodor-Fontane-Archiv is the Universität Potsdam.
According to PR-model, fontanearchiv.de is ranked 319,472nd in multilingual Wikipedia, in particular this website is ranked 27,307th in German Wikipedia.
The website is placed before mphtj.gov.my and after travelweekly-china.com in the BestRef global ranking of the most important sources of Wikipedia.