Does Twitter Change the Concept of Audience?

My students turned in reading journals today, some using twitter as their medium for the first time. I haven't had time to read through all of them but am excited about one in particular that I have seen. One young lady decided to twitter a conversation between herself and Walt Whitman. She read (and struggled to understand) "Song of Myself." I'm interested in reading her questions to Whitman and how she answered them through his persona.

While I was quickly scanning her twitter page, I was drawn into other twitters I have received over the past day or so. By the way, can I actually say I receive twitters? Do those tweeters actually intend to write only to me? I have no idea who will read my twitters at any given time, and I have no inkling of who will decide to follow me today or tomorrow; therefore, I am not writing to a particular audience. So is Twitter changing the concept of writing for a particular audience. How do you know who will read your tweets? Hmmmm.

I have some other twitter questions, but this one is at the forefront of my mind at the moment. What motivates us to choose the people we follow on twitter? For whom do we want to be an audience? I have chosen others in my profession, a couple of friends who are online and tweet, and some people I think have their fingers on a pulse point of our American society.

I ran across Bill Gates' Twitter today and decided to follow him to see what he talks about. (I do question whether or not Bill is actually Bill or if someone is writing as Bill.) Then I decided to see who he follows. He's influential; he's wealthy; for better or for worse, he is a notable American. He has 17,824 people following him on Twitter. So who does this American icon follow? He only follows 45 people/organizations/groups! They include many names I do not know or recognize, Macworld, Iphone Game Play, Scott Hanson (Sr. engineer at Dell), JeanPaulSatre, Darrell Jordan-Smith (VP with Sun Microsystems), and my personal favorite, Darth Vader. What does this say about Bill? What does this say about Twitter users' choice of audience? What does this tell me about how technology is changing the concept of audience for me as a writer?