Well, he has 4200 followers who read his twitter stream and he runs a prominent trader website. Combined with the CEU and RINO debacles, there's no doubt his tweet has an outsized effect on short term support for the stock price, IMO.
That said this drop can be a healthy thing for the stock, heck even an attack article would be healthy at this point because it would take the damn issue off the table, and would be weak stuff. Might even force the company to step up a little more, not that I have any real complaints re management or the fundamental performance of CCME.