Twitter has tapped a new pleasure center in the human brain at the intersection of cell phones and the Web.  That’s a big deal, I think.  Instant Messaging was an interface that tapped a new pleasure center in the human brain when all the computers got connected.  Social networking was an interface that tapped a new pleasure center in the human brain when digital photography hit.  Now it’s happening again, perhaps.  Twitter is first with the application, growing fast, and they NAILED the name, which can be a brand and a verb.  Investors get in if you can.