As educators consider using social networking sites, like Facebook, for educational innovations, they must be aware of possible vulnerabilities associated with the blurring of social and professional boundaries. This research uses social domain theory to examine how students rate the appropriateness of various faculty postings, behaviors, and responses on Facebook when used for educational purposes. Results were consistent with expectations described by social domain theory. Principal Component Analysis found scenarios inter-correlated within three major components, with the extracted components showing face validity for conventional, personal choice, and moral domains. Students generally found faculty Facebook postings related to conventional issues more appropriate than postings related to personal choice and moral issues. The introduction of a privacy setting was also an important consideration for some scenarios. Older students and females were more likely to find some conventional postings and personal choice intrusions by faculty more inappropriate than younger students and males. Furthermore, students who disagreed that faculty should be more accessible on Facebook were more likely to find conventional and personal choice scenarios inappropriate, suggesting they would prefer a firm boundary between faculty use of Facebook and their own social use of Facebook.