Post-9/11 US intelligence reforms take root, problems remain

WASHINGTON (Reuters) - U.S. intelligence agencies will forever be scarred by their failure to connect the dots and detect the Sept. 11 plot, but a decade later efforts to break down barriers to information-sharing are taking root.

Changing a culture of "need-to-know" to "need-to-share" does not come easily in spy circles. Some officials say they worry, a decade later, about a future attack in which it turns out that U.S. spy agencies had clues in their vast vaults of data but did not put them together, or even know they existed.