When Cardinal Joseph Ratzinger was elected as pope last year, some Internet users who logged onto Wikipedia to see what he looked like found a rather different image: that of the evil emperor from "Star Wars."

The prank lasted only a minute or so before someone fixed it, but it highlighted one of the chief problems faced by the online encyclopedia: How to remain open enough that anyone can contribute entries and edit them while also keeping pranksters at bay.

In the coming days Wikipedia will begin using a new system at the German version of its Web site that it hopes will fix that problem. If successful, the system is likely to be introduced at Wikipedia sites in other languages.

At the German site, users who have been registered for four days or more will be able to flag a recent entry as being correct and unvandalized, effectively locking it for a period of time. People will be able to update the entry with new material, but it won't be visible as part of the main entry until another trusted contributor has flagged the updates as being correct.

Four days may not seem like a long time to become "trusted," but it should be enough to deter troublemakers who come up with an idea to deface the site on a whim, said Jimmy Wales, Wikipedia's founder, at the IDC European IT Forum in Paris on Tuesday.

The idea isn't to flag all of the half million or so entries on the German site, just the contentious or topical ones likely to attract attention-seekers, he said. People who visit the entry will be able to see that it's flagged as vandal-free, and have the option to click through and see the recent additions that have not yet been vetted.

He unveiled the German plan in August at the Wikimania conference in Cambridge, Mass., and it's likely to go live any day now.

"I'm just off to look at the software to see if it's ready," Wales said Tuesday. The exact details are still being worked out and the flagging system may be updated even after it goes live, depending on what works best, he added.

It's one of several measures that Wikipedia has taken to improve the quality of its content, some of which have drawn criticism for making the encyclopedia less open. At Wikimania, Wales also talked about creating "stable" or "static" pages for entries that are considered complete, to help people who want to cite them in published works.

The IDG News Service is a Network World affiliate.