Just because they're following you on Twitter, it does not mean that they are paying attention to you.
In a world of Social Media, mass collaboration, sharing and conversations, does anyone find it in the least bit interesting how little of that is really going on among those who rack up the largest followings and conjure up the most mass media attention? When Twitter first came out, there was some commonly held philosophies around following back those who are following you (almost as a common courtesy). The problem was, as more and more people joined the online social network and communications platform, the harder it was to follow back everybody and still be able to be engaged in any real level of "conversation" (you can read more in the Blog post: The Trouble With Twitter - Confessions Of A Twitter Snob).
Most people are in it for themselves.
Personal anecdote: as the book launch for Six Pixels of Separation nears, I had some high level conversations with others who have books coming out in terms of formulating some kind of marketing initiative around sharing and helping one another reach our goals by combining efforts. Upon listing out many of the people with books in the marketplace (or those who have a book coming out), someone sniped back that one of the individuals mentioned actually doesn't help others out at all. They're in it for themselves.
It should give you pause.
On countless occasions you'll read a tweet where someone says, "I can't believe @internet_celebrity is following me!" (keep in mind we're not discussing those real world celebrities who either follow everybody, but never respond or those that have hundreds of thousand of followers but who follow back only a handful). So, how do these Twitter elite really manage hundreds of thousands of followers and conversations?
They're simply filtering you out.
And that is the reality. With Twitter's open API, it has given rise to many third-party applications (like TweetDeck and Seesmic Desktop) that enable a Twitter user to create groups, and that's exactly what they're doing. Very few of the Twitter elite ever look at their full Twitter stream. They're creating a group for their handful of "real" friends or people they want to be connected to. They're also using the amazing power of Twitter Search to create alerts for their personal name, their company, brands and services. This way, if anyone does mention them (whether they're following them or not), they can be notified and respond as if they're really paying attention to their full Twitter stream.
The next generation of the Social Web is all about filters and aggregators, so don't be insulted.
Countless Blog posts and Podcast rants have covered the discussion that a real personal brand is not scalable, so this is what it comes down to. People have finite time and limited ability to engage full-on in conversations (afterall, they do have to earn a living at some point), so the individual who can best manage their personal brand and the myriad of conversations is faced with the reality of having to be ruthless in their Social Media diet.
The bigger question is this: how much longer can we continue to use the words "Social Media" if every day, the majority of the power users are doing everything they can to filter out and aggregate their personal preferences - essentially rendering them less social?