Transportation:
Goeuro: Compare times and costs for train, bus, car and flights
Busliniensuche.de: Find and compare all long distance busses from and to Germany
Blablacar.com: commision-free international carpooling
Hitchwiki.org: find and recommend the best spots for hitch hiking

Tours and Adventure:
Backpackers United: Backpacker-Hostel Networks und Hop-on Hop-off Busses all around the world
Berlin Trails: Individual und exciting Berlin Tours
German Places: Explore Germany
Jugendreisen Leipzig: Leipzig is culture, science, history - and much more
Nightcrawlers Berlin: Unique neighbourhood tours and exceptional guided walks, especially to explore the nightlife of the capital

Friends and Cooperations:
Visa Germany: get germany visa information

Useful information:
Health insurance: get an overview of the german health care system
Students insurance: get the best health insurance for your studies in germany

Hostels
Germany
  Backpacker Berlin
  Die Fabrik Berlin
  Ferdinands Homestay in the Saxon Switzerland National Park near Dresden
  Heintzes Töchter Hostel Schwerin
  Jägers München
  Kangaroo Stop Dresden

Austria
  Strawberry Hostels

Czech Republic
  Poetscorner Hostel Olomouc
  Czech Inn Prague
  Sir Tobys Hostel Prague
  Miss Sophies Prague
 
Poland
 Grampas Hostel Wroclaw
 Mosquito Hostel Krakow
 Oki Doki Hostel Warsaw
 3 Brothers Hostel Cieszyn

Hungary
 Apartments in Hungary

Italy
Mariahome Bed and Breakfast Bed and breakfast in Rome, authorized by municipality of Rome, breakfast, wifi, info, photos, map

Ukraine
 Mini Hostel Odessa Your hostel at the Black Sea

Serbia
 Hostel Magic Belgrade

UK
 Ambleside Backpackpackers

South East Asia
 FEEL AT HOME BACKPACKERS Top Quality Independent Hostel in Singapore and Thailand