Here's the crucial way Twitter differs from other forms of communication (post, email, phone, face to face). With the other forms, you first find the person you want to communicate with, then direct the words at them.
With Twitter, the people are almost impossible to find first. They use aliases, they compress their real names, even the best directories are hit and miss. Besides, they're probably not paying attention. As for lists, they don't list people – they simply list fragments of conversations.
So, with Twitter, you can't find the people first. You have instead to find the conversations either through targeted searches or through a laborious process of following and listening. Once you find the conversation, you're likely to find people interested in it.
If you think this sounds familiar, it echoes the 'situational theory of publics' articulated by James Grunig a quarter of a century ago. Publics form around issues; people gather around conversations. It may not be intuitive, but it makes sense.
PR Studies 
Another way would be to start the conversation and wait for others to find us.
I have been reading the new approach to the situational theory, “situational theory of problem solving” by James Grunig and Jeong-Nam Kim. It fits even better to our online behavior.
Personally I am still focused on values and values systems, both utilitarian and psycho-social values, which I believe serve as a means to identify publics more clearly.
You’ve got this all wrong, I’m afraid. Twitter is about followers and the followed – how passive and old-fashioned is that? From Mr Fry, a national treasure, to Barack Obama, a world leader who’s the most-followed person on Twitter while never having bothered to Twitter in his life, the medium encourages disengagement (in Obama’s case at both ends – followers and followed).
In reality, Twitter is a platform that creates an illusion of interaction and participation while facilitating the emergence of a new elite that’s more arrogant and more remote even than that which it replaces. For most of us, entering the Twitter-den is a lure that sucks us in…
If you would like to debate this – let’s do it properly and constructively. That’s an offer and a challenge: online or in front of an audience. Let’s put Mr. Grunig to the Twitter test.
I think it is for both it can be great for conversations but also can be used to market and this involves follower numbers.
I came across a very interesting webcast exploring the culture of conversation theough social media. it raises some very valuable and insightful points, much of which you touch upon in your post. Take a look at it, makes for intersting viewing http://prperspectives.tumblr.com/post/398433612/exploring-social-media-in-pr
This is a very simple example that shows the power of the modern media in driving these conversations. Click on this link and read the adverts at the bottom – Google creates and places these on the basis of the words it finds on the page – the web site owner is not involved at all in selecting the adverts.
http://www.photocake-occasion.co.uk/Products/Labour.html
~Mr Bailey
I think it is about both, people and conversation
sometimes we follow the person
sometimes we follow the conversation
dont you think?