A bold experiment by the Los Angeles Times to give its readers the chance to review and rewrite its online editorials has been called off after just two days because users flooded the site with foul language and pornographic photos.

The newspaper launched its 'wikitorial' last Friday, with an editorial calling on the Bush Administration to have a clear exit strategy from Iraq. Wikis, based on the Hawaiian word 'wiki wiki' for 'quick', are online communities that allow their users to collectively write and edit articles, the most famous being Wikipedia, the online encyclopedia.

In the end, the newspaper had to pull the page in double-quick time. Although its readers contributed thoughtfully to the debate to start with, and website staff were able to filter out occasional profanity, the site came under full-on attack late on Saturday night after a posting on the Slashot.org "news for nerds" site.

At 4am on Sunday morning, when its website staff had gone to bed, the newspaper admitted defeat and replaced the pages with a brief message explaining that visitors were posting inappropriate material. "Thanks and apologies to the thousands of people who logged on in the right spirit," it said.

The newspaper had admitted before Friday's launch that it did not know where its "nutty" idea would lead and accepted that it might backfire.

"Plenty of sceptics are predicting embarrassment," it said in an introductory article. "Like an arthritic old lady who takes to the dance floor, they say, The Los Angeles Times is more likely to break a hip than be hip. Nevertheless, we proceed."

The newspaper said this morning that the experiment had not been judged a failure and could yet be revived with stronger safeguards.

Steve Outing, senior editor at the Poynter Institute, the Florida-based online journalism think-tank, applauded the wikitorial experiment but said that wiki software was most suited for factual information that can be gradually built up by a group of users.

"Trying to do that with an opinion piece doesn’t seem to make a whole lot of sense," Mr Outing said. "People with competing views would just try to get their particular viewpoint published and someone would go in and change it."

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