I first thought that something with my wordpress/statify installation isn't right or that I have overseen some configs, because statify wouldn't work. It told me all the time "Werte werden gesammelt....".
After reading the documentation I found that part which tells that logged in users are not counted. Because I am running a "Members only"-Blog this nice plugin was completely useless for me and even though I know it isn't the nice way I removed the if-condition checking for logged in users.
Perhaps you, Sergej, would consider to make this condition configurable? Would have saved me a lot of research and I will be able to use your nicht plugin in the future.
P.S.: This post is also for everyone who is as dumb as I was and overread this part of the official documentation.