You don't get much value out of Twitter if you just post for the sake of posting. It's like e-mail. If all you used it for was writing to a penpal, then there's limited value there. But.. most people have evolved beyond that.

My grandmother would never have seen the point of e-mail beyond sending "letters" to each other.. but we all know now it goes deeper than that.

People who don't see extended value in Twitter now are like my theoretical grandmother and her myopic view of e-mail.