When her neighbor's cat Bert was abducted and set on fire three years ago, Alison Gianotto was outraged. "I was disgusted with the human race," says the Del Mar, Calif., software developer. But then, she says, "I was completely blown away by the caring people showed" when she appealed online for donations to help pay the $5,000 vet bill for Bert, who died at the hospital two days after the attack.

Frustrated that the cat's killer was never caught, Gianotto, 28, launched pet-abuse.com to save other animals from Bert's fate. The nonprofit Web site, which lists 3,000 cases of animal abuse around the country, draws more than 1.5 million hits per month. "I wanted to document the names of those arrested and sentenced," Gianotto says. She urges rescue groups to check would-be pet adopters for past abuse charges. "When a shelter e-mails us that a convicted abuser came in to adopt but was discovered in our database, we consider that a victory," says Gianotto. Visitors to the site can also look up the names of abusers in their own neighborhoods. "A couple of women discovered the guys they were dating had animal-cruelty convictions," she says. "They broke off the relationships pronto."

Diane Balkin, a Denver deputy DA., has even consulted the Web site to help prosecute abuse cases. "Alison's database is the best out there," Balkin says. "She's teaching people to see animal cruelty as a public safety issue."

Gianotto, who shares a townhouse with her husband, Louis Garcia, 41, a private detective, and eight pets, five of them rescued (including a calico cat, a brown rat and two tortoises), will never forget the animal she couldn't save. "I wanted to turn the tragedy," she says, "into a tribute to Bert."