NSA Sweep "Waste of Time,"?

Here's an excellent post on Defense Tech reviewing the NSA wiretaps. Defense Tech: NSA Sweep "Waste of Time," Analyst Says

It'd be one thing if the NSA's massive sweep of our phone records was actually helping catch terrorists. But what if it's not working at all? A leading practitioner of the kind of analysis the NSA is supposedly performing in this surveillance program says that 'it's a waste of time, a waste of resources. And it lets the real terrorists run free.'

Even if tracking who everyone is calling is legal, he argues that the technique is so imprecise that it will trigger massive rights violations as a fog of false positive signals lead law enforcement and intelligence agencies to target innocent citizens.

Even if the NSA datamining dragnet is thoeretically possible, what are the chances that it can be run cleanly and optimally? There are so many dangerous dimensions to this story, it boggles the mind.