Facebooks potential to ruin (or make) your business is a common news topic. Content linked to and posted on social networks is just as likely to be malicious as the rest of the web. With malicious apps, clickjacking, and theft of accounts, there is every chance your friend didnt intend to post that link. Education is the best defence, but policy and, just as importantly, good behaviour is still key. Banning social networking from all corporate systems will not help.”]
Source: https://nakedsecurity.sophos.com/2012/06/21/how-secure-access-social-networks/