Nowadays modern Internet technologies play an important role in our life. The present article deals with the peculiarities of hashtags as new text format used in social network. The article presents characteristic features of hashtag text, classification of hashtag functions, types of hashtags according to their construction and the position of hashtags in the post. Different types of hashtags were subjected to the analysis. Continuous sampling method, descriptive qualitative and quantitative analysis allowed the authors to concluded about hashtags as linguistic tools. As a result, five hashtag functions and six hashtag types were identified. These findings would help to understand modern online discourse and to prove the idea that hashtags are considered as meaningful elements of social network communication.