Redmond (WA) - Microsoft has filed a lawsuit against three unnamed spammers who used the company's Hotmail service to send out unsolicited bulk e-mails as part of a stock fraud scheme.

Three John Does are named in the suit, who allegedly sent spam e-mail messages to millions of people, including Hotmail users, making up a story about certain stock prices headed on the way up.  It's a tactic known as "pump and dump".  Individuals buy volume quantities of cheap stocks and then try to artificially inflate their prices.  According to PC World, it's the fastest growing kind of spam.

While Microsoft has no legal obligation to prevent spammers from using its Hotmail service, the software giant hopes to set an example to bulk e-mailers.  It also wants to show its customers that it wants Hotmail to be as clean as possible with regard to spam.

Microsoft filed a similar lawsuit in 2003, which ended in an unclear result.  It then took legal action again in 2004 on the heels of the CAN-SPAM act.  That suit did little to deter the thousands of spammers that still exist, though.

Microsoft wants the three defendants, whose identities have not yet been determined, to pay damages and agree to prevent from sending spam to Hotmail users in the future.