This is a really funny article. The claim is that Twitter is dangerous because people at work could accidentally reveal internal trade secrets by using it.
This kind of argument happens alot but the construction involves a logical fallacy called Ad Hominem. This happened when the writer Michael Krinsman attempted to discredit Twitter by drawing attention to the characteristics of the people who are using it.
This same kind of reasoning in the office place is often considered paternalistic and leads people to make statements like “Coffee makers are bad because employees can burn themselves or even burn down the office!”
A popular use of this fallacy in context of Krinsman’s use was expressed in this Reuters headline: Facebook Costing UK Businesses $264 Million in Lost Hours. Obviously the problem is not to be blamed on Facebook. In this case, the problem is also not Twitter and certainly Twitter is not a dangerous threat.