Watching ones words is always a smart idea, but with the advent of social media and the internet, the temptation to speak out is just too great. Sites like Twitter make it easier than ever to find like-minded people, enter debates, or simply voice an opinion. Its reached a point where people can do more than read those words; they can practically predict what side a person will take.
Research conducted by the Queen Mary University of London gathered data from nearly a million tweets over the course of roughly two weeks; from that data, they reasoned that there was a correlation between a persons political party of choice and the words they used regularly in their tweets. Liberals were far more likely to talk about their emotions and express their individuality and had no problems littering their tweets with obscenities. Meanwhile, conservatives regularly brought religious concepts like god and psalms into the mix; more importantly, they emphasized collectives via words like we and our, compared to the I and me used by liberals.
Its not hard to see how that data can be used by the politically-minded. Reading into the tweets of the people and by extension, the psychology behind them means being able to tap the mindshare and swing them over to certain causes. Taken to extremes, maybe someday activists will be shaping the future in 140 characters or less.