Facebook page admins always ask themselves if legal information has to be provided. The legal frame is not fully clear yet. Regardless, at Big Bang & Whisper we decided to link not only to an imprint in our info section but also to implement a page tab with legal information. We trust in the compentence of eRecht24 where a free facebook imprint generator is available. Thanks, eRecht24!
The facebook experts at allfacebook.de collected some valuable information. Check out their (German) article here: Update zu Massenabmahnungen wegen Impressumsfehlern bei Facebook