I do not know XING that well, because I only joined it a few months ago and have not been very active there so far, but that is changing at the moment.

XING is a German network, that also features other languages: of course English, but also Espanol and even Chinese!
There are thousands of people online simultaneously and the possibilities are many. It has to be said that some of the features are ‘Premium’ content ( which I do not know much about ) that is being charged for.
You need to know German well to get along there!