a while ago (when the the internet was young) people used to try and foil the authoritys with "spookfodder", a pile of potential "computer monitoring sensitive" keywords that would trigger a response from any system monitoring your mail, then they appended it to almost everthing sent via the net so, pictures, e-mails, irc etc, often sending spookfodder abroad just to make sure it got checked, the idea is that with so many false positives it rendered monitoring useless, they just don`t have enough people to physicaly check every mail/posting sent through the internet, you can enhance the effect by posting strings of random numbers etc, then they have the added bonus of trying to work out if thats a message to someone
eg:
165,43,987,56,3,56,by,ce,mr,xp,vy,ze,zp,11,85,64,47,73,69, bin laden, bush, bomb
naturaly it would not be responsible to do this, just saying it can be done, personaly I know I could send messages over the net and they couldn`t even begin to work out where they where, how they where encoded, or how to unencode em, monitoring is only going to catch the dumbest of the dumb or have them chaseing shadows all the time, in other words, once you know they monitor communications you can negate it or even hinder the opposition by wasting their time and resources, far simpler and effective to rely on conventional counter terrorism methods.
Mentor.