Citations to social media can usually be limited to the text. If a more formal citation is needed, a reference list entry may be appropriate. In place of a title, quote up to the first 160 characters of the post. Comments are cited in reference to the original post.
Private content, including direct messages, is considered a form of personal communication and should be cited as such.
In the reference list, include the real name and a screen name, if both are available. In the text, cite the name under which the entry is listed