12-Jul-15: What exactly happened over Independence Day?

Source: CNN, June 26, 2015

The FBI and the U.S. Department of Homeland Security warned local law enforcement agencies ahead of time [see this June CNN story for instance] to be alert for attacks around the July 4 holiday.

No such attacks happened. But Reuters, in a vaguely worded report quoted "a national security source" saying

multiple overseas plots by Islamic State sympathizers had also been halted in recent days. [Reuters, July 10, 2015]

We might find that details get released over the coming weeks and months:

FBI Director James Comey said Thursday that the FBI was able to thwart attacks tied to July Fourth, CBS News confirmed. Comey would not give details on attacks or arrests but did say in the last four weeks the FBI arrested more than 10 people who are products of the Islamic State’s online recruiting. Some were focused on the Fourth of July. Not all are charged with terror offenses, the FBI director said. “I do believe we disrupted efforts to kill people in connection to the Fourth,” Comey said. He said he believes their work saved American lives. “They’re averaging 50 people a day internationally that ISIL, through their mass media campaign, is successfully recruiting people,” former FBI agent Manny Gomez told CBS2’s Dick Brennan. “And it sounds like they have successfully once again recruited individuals that were planning to launch attacks during the Fourth of July in random places in the U.S.”... Comey said the ISIS’ online message and social media is so unpredictable that it can be hard for federal authorities to ever be sure of their plans and it’s difficult to track the lone wolf. “We have limited resources to identify, investigate and stop all of them,” Gomez said.[Source: "CBS News: FBI Thwarts Terror Attacks Tied To 4th Of July", July 9, 2015]

How often have words like those ("we don't have enough resources") been sounded by public officials responsible for blunting the penetration of Islamist groups into mainstream society?

And how involved are Americans in the workings of the Islamists? Here's one stab at quantifying:

“I have been doing this for 45 years,” said Francis Taylor, the undersecretary of intelligence and analysis for the U.S. Department of Homeland Security. “I’ve never seen a terrorist organization with a kind of public relations savvy as ISIL.” ISIL is the government’s preferred acronym for the Islamic State, which is also known as ISIS... [T]he Islamic State’s public relations savvy has drawn 180 Americans to join the group, Taylor said in his prepared remarks. ["Islamic State’s command of social media called unprecedented", McClatchy Group, June 3, 2015]