The article aims to identify and compare behaviour patterns of Polish social enterprises, especially those operating in the IT branch and using social media to communicate with their clients. The research consisted of a multidimensional qualitative and quantitative content analysis, including Cramér’s V correlation coefficient based on chi-squared statistic, also suitable for nominal data types. The article focused on client communication content created and placed on social media by Polish social enterprises from the IT and other branches. The research sample comprised 301 entities. According to the adopted assumption, the statistical research (correlation analysis) results showed certain behaviour patterns within the scope of the analysed area and revealed significant circumstances that affect communication. Due to the profile of professional competencies, the IT industry prefers communicating via social media, which aims to formulate a concise and precise message. Social enterprises in the group of the most economically effective entities have a unique way of using social media. They choose the most popular social media and, at the same time, to some extent, expand their communication to more specialised platforms. The applied approach is a new way to analyse social enterprise activities in social media. The analysis findings contribute to a greater understanding of connections between the discussed phenomena. The presented research procedure can be applied to determine the impact of other competencies of the analysed entities on sustainability communication in social media. According to research, IT entities enrich the current trends in social media use by social enterprises. The research results may be useful for banks, investors and public institutions forecasting the success of social enterprises and making support-related decisions. The scale and scope of the use of social media platforms for communication with the market may be a criterion in measuring the chances to commercialise goods and services offered by social enterprises.