Howard Carmack, known as the "Buffalo Spammer," was found guilty by a Buffalo jury on 14 counts of identity theft and forgery,
a spokesman for New York Attorney General Eliot Spitzer said.
Carmack was the first defendant to face charges under the state's new identity-theft statute, condemned for sending out 825 million bulk email messages using stolen identities and forged addresses.
Carmack faces a prison sentence of three-and-a-half years to seven years, and he will be held in Erie County jail until his sentencing on 27 May.
Internet provider EarthLink officials testified in the criminal trial as well, after having won Internet provider EarthLink won
a $16.5m (13.5m Euro) judgment against Carmack last year.
Irritating mail curently accounts for the 60 percent of all email traffic, according to filtering company Brightmail, and perhaps
the latest updates regarding Carmack's trial will lower that percent.
Many of Carmack's alleged activities are illegal under a national anti-spam law that took effect in January, seven months after he