30-year-old Amir Gans, is accused of sending unsolicited marketing emails and contributing up to 50 percent of Israel's spam problem. Industry watchers have largely praised the move.
"There needs to be more international action against spammers to send a clear message that their behaviour will not be tolerated," said Graham Cluley, senior technology consultant at anti-virus company Sophos. "No spammer should be able to sleep at night through fear of the authorities knocking at their door."
Microsoft's lawsuit is for nearly $500,000 and mirrors a suit filed last year by Israeli Internet Service Provider (ISP) Golden Lines for just under $60,000.
Gans company, New Approach stands accused of sending over 500,000 spam emails in under a day. Golden Lines argued that the activity damaged it business when anti-virus firms blocked its emails.
Israeli news reports suggested that Gans lodged complaint against Microsoft after the company demanded to know how many email messages his company had sent to users of its Hotmail services. Days later Microsoft's own lawsuit was filed.
Earlier this month SC reported Microsoft filed a lawsuit in conjunction with Viagra vendor Pfizer against companies who allegedly send Viagra spam.