Spock, a search engine for finding people, mixes search with social-networking tools like personal profiles and tagging. But you don't have to join to have a profile on Spock. In fact, you may be shocked to see what your profile says about you.

For example: Mike X. is a fat, retarded pimp who likes screwing prostitutes. Mary Y. works in a strip club downtown and owns a vibrator. Joe Z. is a man-whore who hangs out at stranger's houses and drinks rum and coke.

If you searched Spock using the real names of these high school teenagers, those are the kind of tags you'd find.

These kids have a few things in common: They, along with 12,000 other people, recently downloaded a "Mad Libs"-like Facebook application and wrote stories about themselves and their friends, filling the blanks with scandalous terms.

But they didn't realize the application was created by Spock, which debuted last week. And they were horrified to discover that Spock used the terms they supplied to build public profiles on them and other Facebook members. (After being contacted by Wired News, Spock erased the tags from many of these profiles, but some were still visible at press time.)

It's not just fun and games. If you searched Spock for the tag "pedophile" last week, blogger John Aravosis' profile would have shown up near the top. The proprietor of the popular Americablog has written extensively about former Congressman Mark Foley. The profile was automatically created by the Spock bot, which crawled sites associated with Aravosis.

In an e-mail, Aravosis says the discovery of his profile on Spock was "terribly disturbing ... and bizarre."

"It's certainly great lawsuit material," he says. "It's still possible that (Spock) picked up on our coverage of the Foley scandal – we were one of the top sites covering it – so perhaps their search engine just screwed up."

After being contacted by Aravosis, Spock removed the offending tag.

CEO Jaideep Singh claims Spock is no different than Google, indexing and aggregating information already available elsewhere on the web. Spock spiders major social networks and public sites, culling text and photos and adding descriptive tags to build your profile. If you've got a page on MySpace, Hi5, Friendster or Wikipedia, odds are good you've also got one in Spock's 100-million-profile database.

But when databases are built by bots and not by humans, mistakes happen. False or malicious profiles set up on other sites will be indexed along with the real ones. Divorced from their original context, tags can take on a life all their own.

Once your content is on Spock it's no longer strictly yours. For example, you can't make your Spock profile private or limit who can contribute to it. Anyone registered with Spock can vote on the tags or photos on your profile. If the 'no' votes outnumber the 'yes' votes, the new content is removed. Otherwise, you'll have to ask Spock's customer service to remove it for you.

"The best way to ensure that Spock will not index web documents about you is to remove all documents about you from the web," notes Singh in an e-mail. "This is no different than Google or other leading search engines."

The potential for using Spock to harass someone or poison their online reputation is real, though not likely to happen frequently, says Greg Sterling, a correspondent for the Search Engine Land news site.

"It's unlikely you'll be subject to defamation or that someone will maliciously tag you," he says. "But it is a possibility. It all goes to the issue of privacy and who's got control."

Singh says the service has built-in safeguards to prevent abuse. For example, Spock sends you an e-mail when your profile has been modified, so you can quickly vote down objectionable items. (If you've never visited the site and claimed your profile, however, you won't get this e-mail.) You can also see which Spock members posted content on your page, and Singh says his customer service team is working hard to identify and remove fake user profiles.

"It is the web, so some people will always try to spam you and do malicious things," he admits. "But the value of people adding tags and content about you is enormous. We want to make sure that the 99.9 percent of content that's valuable to users isn't washed away by the 0.1 percent that's spam."

Over the next few weeks, Singh says Spock will roll out an internal reputation system that identifies users whose tags and photos are consistently voted down; as their reputation declines, they will lose the ability to add new content. Spock users can also flag abusive users and report them to customer service. Singh believes a combination of automated tools, customer support and community policing will keep Spock relatively clean.

But just as big corporations regularly scour the web to gauge whether their brands are being abused, individuals will need to become more aware of how they are portrayed on people-search engines like Spock, Wink and Pipl, adds Sterling.

If Spock succeeds in becoming the Google for people search, you may have no choice but to sign on. Your reputation may depend on it.