Facebook's former 'conscience' Chris Cox quit last year after clashing with Mark Zuckerberg. Now that he's back, employees wonder if things will be different. (FB)

· *Chris Cox, a beloved Facebook employee who quit a year ago amid clashes with Mark Zuckerberg, is returning.*
· *Cox and Zuckerberg disagreed with the direction of the company, including on plans to more closely integrate its apps.*
· *His return raises the question of what changed: Is Zuckerberg open to concessions, or...