On Saturday, a user on Twitter posted threats about specific flights.

These terroristic tweets were taunting and often vulgar with careless disregard for the safety of numerous people. Authorities were contacted and an immediate investigation was started. Multiple flights were halted, Flights from Portland Portland and Milwaukee were identified and Atlanta Airport was checked for bombs.
Targeting various airlines, the threats moved on from Delta Airlines to Southwest Airlines.

Good practice – the verbiage used by Southwest is good communications/social media verbiage to use on Twitter when responding to immediate threats.
User cited supposedly specific information on how the plot was carried out.

Taunting the safety of passengers on a public forum is bad.

In the end, the person making the threats identified a specific address of location. Again, taunting law enforcement.

Easily found on Google Maps, Chicago Police was dispatched to this address to verify information.

As I predicted, the address did not yield the subject.
Sounds like “SWATTING” to me – http://www.fbi.gov/news/stories/2013/september/the-crime-of-swatting-fake-9-1-1-calls-have-real-consequences/the-crime-of-swatting-fake-9-1-1-calls-have-real-consequences
In my opinion (and how you should interpret this story is simple): It takes is 140-characters to send you to jail.
From the intel POV: Lots to glean from the info/data posted in these tweets.
From the safety POV: Lots of operational assets to mobilze.
From the Emergency Management POV: Lots to coordinate with various all-hazards public safety agencies in multiple places.
This would be a good time to remind you of DHS’ phrase – “If you see something, say something”.
Remain vigilant my friends.
@rusnivek