There have been news reports of people getting robbed because they set their status to something like: "going to las vegas for 5 days of debauchery and tomfoolery! Woo hoo! Won't be back until nov. 10, so don't come to my house. I won't be there." Not to mention, the numerous cases of people getting fired or getting dumped by their significant other over FB statuses and clues.
people post their cell phone numbers with the privacy settings turned off, and the biggest, most overblown news concern, is that facebook makes it easy for your info to to be passed onto advertisers and third party apps.
facebook makes it easier for people to "google" you.