The newest revelations regarding the NSA surveillance programs have focused on XKeyscore, described by the NSA as its “widest reaching” system for collecting intelligence from the internet. As Glenn Greenwald notes: “XKeyscore provides the technological capability, if not the legal authority, to target even US persons for extensive electronic surveillance without a warrant provided that some identifying information, such as their email or IP address, is known to the analyst.”(Guardian. See Slate coverage here).
The NSA training materials (available here) are rather interesting. When presenting the criteria for targeting individuals for surveillance under XKeyscore, the NSA includes:
“Someone searching the web for suspicious stuff.”
Of course, “suspicious stuff” is a technical term, so it is difficult to know what it might include. Thankfully, the NSA has assured the Guardian that “there are multiple technical, manual and supervisory checks and balances within the system to prevent deliberate misuse from occurring.”