If you are still relying on Google to snoop on your friends, you are behind the curve.

Armed with new and established Web sites, people are uncovering surprising details about colleagues, lovers and strangers that often don't turn up in a simple Internet search. Though none of these sites can reveal anything that isn't already available publicly, they can make it much easier to find. And most of them are free.

Zaba Inc.'s ZabaSearch.com turns up public records such as criminal history and birthdates. Spock Networks Inc.'s Spock.com and Wink Technologies Inc.'s Wink.com are "people-search engines" that specialize in digging up personal pages, such as social-networking profiles, buried deep in the Web. Spokeo.com is a search site operated by Spokeo Inc., a startup that lets users see what their friends are doing on other Web sites. Zillow Inc.'s Zillow.com estimates the value of people's homes, while the Huffington Post's Fundrace feature tracks their campaign donations. Jigsaw Data Corp.'s Jigsaw.com, meanwhile, lets people share details with each other from business cards they've collected -- a sort of gray market for Rolodex data.

Some people have come across dirt on their loved ones without even looking for it. Doug Orlyk, a 42-year-old librarian in Bensenville, Ill., recently turned to ZabaSearch to find his new boyfriend's address so that he could send him a card. Instead, he found out that the boyfriend had been lying about his age -- he was 43 years old, not 35 as he had claimed to be on the dating site where Mr. Orlyk had met him. "I thought, 'You're a liar! You're older than I am!,'" Mr. Orlyk recalls. His new relationship ended soon thereafter.

Others rely on the Web to gather information on the job. Art Feagles, a technology specialist at the Cate School, a private high school in Carpinteria, Calif., runs the computer system for the alumni and development office. But his colleagues, who fund-raise for the school, keep tapping him for another tech skill: researching potential donors online.