Is watching Twitter taking your eye off the ball ?
I would be curious to know what *exactly* these law enforcement agencies think they're getting, when they start monitoring Twitter.
I know the average terrorist, or criminal is - almost by definition - not the sharpest tool in the box, but the idea that they would use a public messaging forum to organise or coordinate anything is fanciful. And that's putting it mildly.
I suspect they are doing in cyberspace *exactly* what they used to do in meatspace. And that's profile people who have "subversive" views, based on their contacts. I also suspect (I am not a USAian, but the UK is a close analogue) that the House Committee for UnAmerican Activites (HUAC IIRC?) never disbanded, but simply changed it's name.
Now if *I* were a bad'un, and wanted to have a secure - and reliable - method of communication, I would investigate using usenet. Anyone who has subscribed to a newsgroup for any length of time will know that some regular posters may as well be writing in code anyway (I certainly can't make out a word of the drivel that gets posted). This also has the critical advantage that - unlike email - it breaks the link between poster and reader, since a smart cookie will cycle through their news servers (with a nod to Googles usenet abortion) meaning the spooks can't tell who a message was intended for, and whether it was read, nor where the reply was posted. And of course you could simply post a random PAR file to a binary newsgroup, which may - or may not - be an encrypted message.