19. The method of claim 9 wherein the step of examining received micro-blog messages for abnormal activity is performed on a computer system.
9. The method of claim 2 wherein the fourth vector is a vector of n+m dimensions comprising: n dimensions that represent tokens of the text message and their frequency of use; and m dimensions that represent metadata concerning the text message, the m dimensions comprising: a first dimension that represents a source of the message; a second dimension that represents a language of the message; a third dimension that represents a time stamp for the message; a fourth dimension that represents a geographical origin of the message; and a fifth dimension that represents an author of the message.