Wikipedia has recorded its millionth registered user for its English-language website and anticipates a milestone double-whammy this week as the millionth article is published.

Users of the online encyclopaedia have been speculating on the date of the millionth posting since November 2004, with some predicting it simply wouldn't happen.

"There simply aren't one million topics in existence," said one Wikipedian, who looks likely to be proved wrong some time today.

Answering questions from the site's users last week, Wikipedia founder Jimmy Wales said the quality of content on the site would be improved with a new article review system.

He predicted the site's content would change eventually as core subjects are covered more comprehensively.

"We'll see a tapering off of new article creation in the large language Wikipedias as more and more 'verifiable' topics are covered. At this point, most changes will be expansions and updates and quality improvements to existing articles.

"But in 10 years, it seems likely to me that many languages which are now quite small will have very large Wikipedia projects. Our community will continue to become more diverse as more and more people worldwide come online."

Predictions for the date of the 2 millionth article, 5 millionth article and 500th language pool are also ongoing.

And in the event that Wikipedia goes under, the earth ends or the site is finally completed "with the sum total of all current and future human knowledge", users have set up a last topic pool with suggestions including "Three easy steps to building your own nuclear weapon", "Quantum black hole safety" and "How to delete the internet in one simple keystroke".

The online encyclopaedia allows anyone to edit and contribute content and has become a powerful online presence since it launched in January 2001.

The site recently blocked access from US Congressional computers - albeit temporarily - after what it described as"inappropriate edits" by staffers, although Mr Wales denied any evidence of "corporate astro-turfing".

The credibility of the site came into question last December by the USA Today founding editorial director, John Seigenthaler, after he discovered a "false and malicious" entry that implicated him in the assassination of President John F Kennedy.

Wikipedia responded by strengthening its registration procedures so that new stories cannot be posted by anonymous posters, and by issuing a new policy on biographies of living people.

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