Contact:
Abgefahren e.V. c/o Jonathan Stock Heinrich-Lüth-Weg 11 23701 Eutin Germany
For technical concerns:
Philipp Gruber
Robert-Blum-Str. 1b
76185 Karlsruhe
Germany
Besides, there is an IRC channel #hitchhiking on EFnet and a Skype chat.
... and the Community Portal takes your "questions, remarks, requests".