An instant message exchange might seem as fleeting as a phone call or face-to-face chat. But, like everything else on the Net, it can have much more staying power than users think. Unlike e-mail, the brief IM remarks that pop up on computer screens are not kept on central servers. But that hasn't stopped companies from developing software that snags every message - including those unflattering to the boss. Interest in IM monitoring is soaring as companies not only look to record important communications but also control information leaks and discourage cyberslacking. Skeptics say it's just another example of how...