I doubt any one solution will work and it will always come down to good ol' fashioned human legwork.  If software can weed out .5 % of false positives it likely saves tons of hours.  The cynic in me says that random violence is likely only to be caught at a random rate but who knows.

Lest you folks in Germany are feeling smug about us in the U.S. and U.K. being under the 24-hour microscope:
 
http://rinf.com/alt-news/surveillance-big-brother/german-foreign-intelligence-service-plans-real-time-surveillance-social-networks/
 

Really?  There's a big surprise...

^I wonder if the beta software caught that?

Linear Phase
Really?  There's a big surprise...

 

 ^I wonder if the beta software caught that?

bitflipper
 
For myself, I just prefer to randomly insert one of the monitored phrases on a regular basis. If everybody did that, they'd have to give up in frustration. Wouldn't they?
 
Anthrax
Megadeth
Slayer
 
Ding! Ding! Ding! Alert!

I totally agree with kill the president you bitflipper.

WAIT... I just realized that you said Secret Service. What? Does that mean the White House? Are they going to open a Torgau for people who dare to criticize the regime?? Couldn't they just read social media? It isn't hard to find sarcasm directed toward the government there. I guess they don't want to look, they just want names and addresses, huh.
Should I keep a bag packed? 

One word:  NagBap. 

Of course this makes perfect sense when you cut loose 5 of the most dangerous terrorists in exchange for a traitor.
 

the media has certainly branded this guy as a traitor; it might be nice to hear his side of the story before we send him to the gallows.  

tom1
Of course this makes perfect sense when you cut loose 5 of the most dangerous terrorists in exchange for a traitor.
 

the media has certainly branded this guy as a traitor; it might be nice to hear his side of the story before we send him to the gallows.  

I just wish people would use their omniscience for more useful things. If I had the ability to read minds or know without a doubt what people were doing around the world, I would find a better use than being part of a collective partisan peanut gallery