This is highly relevant for the conspiracy theorists.

Random number radio stations.

http://en.wikipedia.org/wiki/Numbers_station

    A numbers station (or number station) is a type of shortwave radio station 
    characterized by their unusual broadcasts, which consist of spoken words,
    but mostly numbers, often created by artificially generated voices reading 
    streams of numbers, words, letters, tunes or Morse code.

Now, if you take a look at any random tweet, you will notice that the location that it was tweeted from changes every time (often in the middle of the Sea). This could also be a hidden chunk of information that encodes/hides other relevant data.

It is certainly not by accident that the lat/lngs change on each Tweet. If I had the time as an experiment, I'd probably try and find patterns between the lng/lats to see if the decimal equivalent means anything? How hilariously awesome would it be if when mapped on a globe, it builds up a large picture. (Fair warning.. this runs WebGL and will most likely nuke your browser for a few seconds http://data-arts.appspot.com/globe-search/ )