"If Facebook allowed users to differentiate between their professional and social relationships and control what parts of their profile are visible based on relationship type, it" could be the end of LinkedIn...
K. Naini, R. Kawase, N. Kanhabua, and C. Niederée. 23rd International World Wide Web Conference, WWW '14, Seoul, Republic of Korea, April 7-11, 2014, Companion Volume, page 559--560. (2014)