Creating a common language for building trust online is the goal of the Protocol for Web Description Resources (POWDER), released this week by the World Wide Web Consortium.

Powder takes a simpler approach than WikiTrust. By using Powder's specifications, a Web site can make claims about where information came from and how it can be used. For example, a site could say that a page contains medical information provided by specific experts. It could also assure users that certain sites will work on mobile devices, or that content is offered through a Creative Commons license.

Powder is designed to integrate with third-party authentication services and to be machine-readable. Users could install a plug-in that would look for claims made through Powder on any given page, automatically check their authentication, and inform other users of the result. Search engines could also read descriptions made using Powder, allowing them to help users locate the most trustworthy and relevant information.

"From the outset, a fundamental aspect of Powder is that, if the document is to be valid, it must point to the author of that document," says Phil Archer, a project manager for i-sieve technologies who is involved with the Powder working group. "We strongly encourage authors to make available some sort of authentication mechanism."

Ed Chi, a senior research scientist at the Palo Alto Research Center, believes that educating users about online trust evaluation tools could be a major hurdle. "So far, human-computer interaction research seems to suggest that people are willing to do very little [to determine the trustworthiness of websites]--in fact, nothing," he says. As an example, Chi notes the small progress that has been made in teaching users to avoiding phishing scams or to make sure that they enter credit-card information only on sites that encrypt data. "The general state of affairs is pretty depressing," he says.

Even if Web users do learn to use new tools to evaluate the trustworthiness of information, most experts agree that this is unlikely to solve the problem completely. "Trust is a very human thing," Archer says. "[Technology] can never, I don't think, give you an absolute guarantee that what is on your screen can be trusted at face value."