Sneering at the virtual lynch mobs that pursue him, Mr. Canter vows to unleash his own electronic mail-bombing robot once again, perhaps this week, to post unsolicited advertisements everywhere in Usenet, a computer network shared by millions of people worldwide.

The husband-and-wife law partners are being pursued not for any illegality in posting their commercial message on thousands of computer bulletin boards. None of this is illegal, and indeed, others are now using similar tactics -- although on a smaller scale.

Rather, they are considered pariahs because they openly expressed disdain for the Usenet rules and "netiquette" and vowed, despite pleas for cooperation, to do so again. They are unrepentant.

It is not their first experience with public scorn. Both Mr. Canter's and Ms. Siegel's licenses to practice law were suspended in 1987 by the state bar associations of Florida and Tennessee for conduct that the Supreme Court of Florida deemed "contrary to honesty." Bar Association Troubles

Both lawyers resigned from the Florida bar in 1988 rather than fight subsequent accusations of neglect, misappropriation of client funds and perjury that were filed against Mr. Canter by the bar. Ms. Siegel said the charges were unfounded and were lodged by a "very rabid bar" out to discredit them for unknown motives.