NEW YORK — The former CEO of a once-popular male escort service website, who pleaded guilty last year to promoting prostitution, was sentenced to six months in prison Wednesday by a judge who said she wanted to send a deterrent message even though she knows the business helped people.

Jeffrey Hurant, who ran the Rentboy.com site, was sentenced by US District Judge Margo K. Brodie in Brooklyn.

‘‘The very thing that is illegal — there is no question it did a lot of good,’’ Brodie said of the website as she also announced a $7,500 fine. ‘‘Almost two decades of committing a crime. That can’t go unpunished.’’