Where’s the fault in making “share” the default setting on Facebook? After all, people who have read 10 years’ worth of scary headlines about email viruses, Internet scams featuring Nigerian princes and phishing websites seem eager to give up their likes, dislikes, kids’ names, embarrassing photos and vital statistics to an audience of a half-billion on the world’s largest social network. However, Facebook has heard its critics get louder regarding its apparently cavalier view of its members’ data.