Agree. But don't fall into the trap of assuming that the entire planet (or even all your customers) are hanging out on Twitter.
It's very good to craft your offerings amongst IT-savvy early adopters - let's be honest, Twitter's primary constituency.
But sooner or later, many companies want to break out into some sort of mainstream. At that point, listening is still very important, but presumably other media are required.
i.e. "The point of need" is not always Twitter.
(I appreciate this is totally obvious, but sometimes the Twitter bubble needs a little poke)