I just returned from 140
The Twitter Conference, held in Mountain View, CA, last week. BTW, despite indications to the contrary, it was the first Twitter for business conference. (Not exactly the same focus as TWTRCON, but business-centric nonetheless.)
The main takeaway for me is that Twitter IS a tool businesses should and will be using.
There are ample case studies all along the continuum, from small businesses such as Naked Pizza, a New Orleans pizzaria that gained notice in local and national press, to enterprise-level companies such as Dell.
If you had any doubt, allow me to reference a recent MarketingProfs poll which reported that "more than eight in 10 Twitter users, most of whom represent small businesses, expect their company's use of the popular microblogging tool to increase in the next six months."
One indication of Twitter's coming predominance as a marketing tool are the number of conferences about it, which now number as many as six. This leaves me to wonder why Facebook conferences aren't following suit. I mean, its value as a marketing tool is being proven even as we speak.
You have to hand it to Twitter founders Biz Stone and Evan Williams. Whether they envisioned the app taking on such major importance as a marketing tool or not, I don't know. Considering their previous success with Blogger though, I'd have to say "once you're lucky, twice you're good."