Wall Street was an earlier adopter of IM, and its popularity continues to soar. In 2003, the NASD joined the SEC and NYSE in announcing that all IM communications between brokers and their clients must be retained for a period of three years, just like e-mail and printed correspondence. Thanks to new IM retention regulations, prosecutors and investigators digging into Wall Street scandals and white-collar crime now have a new evidence pool to dive into: instant messages.