Google wants Web site owners and developers to watch out for the latest online peril, social profile spam.

Social network users who haven't yet established online friendships with individuals going by names like BuyHerbalViagra and WebCamVixen97 may not be familiar with social profile spam.

But social network operators have to deal with more and more of these user accounts -- or abuser accounts -- every day.

As Google's search quality engineer Jason Morrison observes in a blog post, allowing accounts of this sort to proliferate risks ruining one's site for legitimate visitors.

"You definitely don't want your users hounded by fake invites to the point where they stop visiting altogether," he said. "If your site becomes filled with spammy content and links to bad parts of the web, search engines may lose trust in your otherwise fine site."

Social profile spam is really just a subgenre of the Web spam and comment spam that has plagued Web sites and blogs for years. But it's more pernicious because users let their guard down when corresponding with supposed friends.

Morrison says that spammers create fake social network accounts for a variety of reasons. It may be that reaching real users requires an account. But it often has to do with taking advantage of the trust users feel toward social sites and online connections to distribute spam links, redirects, and malware, he explains.

It's not just major social networking sites and services that face this problem, says Morrison. When new user accounts get created using content management systems such as vBulletin, phpBB, Moodle, and Joomla, the account creation process may auto-generate Web pages that spammers can exploit. Risks of this sort rise if the CMS system in question relies on insecure add-ons or plug-ins or has been improperly configured.

Morrison advises Web site operators to do what they can to harden their sites against social profile spam. Possible steps include: using CAPTCHAs to discourage automated account creation; blacklisting accounts linked to spam domains; guarding against cross-site scripting vulnerabilities; using the "noindex" tag on profile pages to diminish the incentive to game Google's ranking system; adding spam reporting mechanisms for users; watching for spammy pages by using Google Alerts and the keyword list Google provides in its Webmaster Tools section; and watching for spikes in specific search queries.

"The social web is growing incredibly quickly and spammers look at every kind of user content on the Web as an opportunity for traffic," Morrison says.

InformationWeek and DarkReading.com have published a report on data-centric protection. Download the report here (registration required).