Today social media is used extensively in both private and professional contexts, with using habits and conventions shaped by the private using context. It is unknown how in the users perception professional social media usage might differ from the private context and which implicit or explicit etiquette criteria apply. With an empirical questionnaire approach (N=99, ages 20-59) we examined the impact of perceived formal correctness, formal politeness and workflow compatibility of social media applications (email, blog and chat) on the acceptance of social media in the working context. We additionally analyzed the impact of personality on users perceptions toward social media etiquette. Therefore we examined correlations between two Five Factor Model (FFM or Big Five) personality traits (conscientiousness and agreeableness) and requirements for formal correctness, formal politeness and compatibility. Linear regression shows that requirements for social media etiquette are strongly influenced by conscientiousness, age and social media expertise. Differences in etiquette are evaluated in regard to formal addressing, correct spelling, acronym and emoticon usage, work disruption and perceived urgency. Furthermore differences in etiquette between different media are explained.