Synthesized answer
The provided passages explain that a user can direct tweets to another user by prefixing a post with an at-sign before the target user's name [1]. They also state that the book discusses Twitter's role in political, economic, and social lives, and examines it as an emergent global communications medium [2].
However, the passages do not answer what questions remain unanswered regarding a user posting a tweet.
Synthesized from the book passages below. Chat with the book on Feynman for follow-up.
From the book
n which Twitter and social media more broadly may be shaping contemporary life. Categories: Computers Pages: 184 Snippet: Social Communication in the <b>Twitter</b> Age Dhiraj Murthy. The dialogue between <b>Twitter users</b> occurs through the at - sign ( e.g. , <b>a user can</b> direct tweets <b>to</b> another <b>user</b> by prefixing a <b>post</b> with an at - sign before the target <b>user's</b> name ) .
Title: Twitter by Dhiraj Murthy Description: Twitter has become a household name, discussed both for its role in prominent national elections, natural disasters, and political movements, as well as for what some malign as narcissistic “chatter.” This book takes a critical step back from popular discourse and media coverage of Twitter, to present the first balanced, scholarly engagement of this popular medium. In this timely and comprehensive introduction, Murthy not only discusses Twitter’s role in our political, economic, and social lives, but also draws a historical line between the…