In the days before Twitter there was an old-fashioned notion of "keeping it to yourself", a time when mothers used to say "If you don't have anything nice to say, don't say anything at all."
Now Twitter's firehose of brain bursts has been switched on, plenty of Tweeters have decided it's high time to do away with their own politeness filters and set their worst thoughts free.
This kind of stream-of-consciousness tweeting has landed tweeps in a whole world of trouble.
Most recently, Liam Stacey, 21, was arrested after allegedly making racist comments on Twitter relating to Fabrice Muamba, the critically ill Bolton player who collapsed on the weekend.
Earlier this year, two British tourists, Leigh Van Bryan and Emily Bunting, were barred from entering the United States after joking on Twitter about “destroying America”.
US special agents also took exception to a comment about “digging up Marilyn Monroe”.
Click through the gallery below for a history of tweets that got their authors in trouble with the law.