I admit, Twitter seemed like a completely ridiculous concept for me for quite a while. I still don't Twitter with regularity, but the majority of business leaders that I know do. We're talking CEOs of big marketing companies to developers within Microsoft. It's as much a marketing tool as anything else.
So, don't knock it unless you understand it. It takes time to "get it", and I'm still not sure I do. Like blogs, there are those that have things like "Descartes is eating a sandwich", but many more with things like "Descartes is at HIMSS listening to a seminar from Epic on EHR" as an example. That has value.