In the context of the Boston massacre (2) we are back to the discussion of "stove pipes" and "dots." After 9/11 there was a general frenzy about information sharing between agencies. This frenzy was largely misguided. The major problem in the 9/11 intelligence failures was not compartmentation and poor thinking. The problrm was poor collection of information especially the lack of effective aggressive clandestine HUMINT persistently targeted at penetration of AQ and friends. Don't tell me that this would be hard to do. If it can't be done because it is difficult then get rid of the expensive agencies that say they can't do it.
Basic Rule: You can't connect dots (data points) that you don't have.
In the eagerness for sharing that existed in the post 9/11 world, compartmentation barriers were torn down and huge networked data bases were built with very wide access given to anyone who conceivably might have a use for the information.
The result was that Private First Class Bradley Manning sitting in an airconditioned hut in Iraq was able to download millions of documents that had nothing to do with his assigned tasks and then disclose them to whomever he wished.
Just remember that there is an unending trade-off between ease of access to material and the security of that material. pl