The co-founder of the popular online encyclopedia, Wikipedia, is poised to launch an alternative and "even better massive encyclopedia" this week.

Larry Sanger's Citizendium aims to weed out biased or incorrect information and obscenities by creating user registration and editorial controls, in contrast to the more open submission process at Wikipedia, where Sanger once worked as editor-in-chief. Citizendium will be an invitation-only site for experts in their field.

"Wikipedia is amazing. It has grown in breadth and depth, and the articles are remarkably good given the system that is in place. I merely think that we can do better," Sanger told CNET's online news site.

"There are a number of problems with the system that can be solved, and by solving those we can end up with an even better massive encyclopedia."

In answer to questions about the new site's relationship with Wikipedia, Citizendium's FAQ section makes it clear Sanger wants to improve on what he sees as problems at Wikipedia:

"Are you attempting to shut Wikipedia down?

"No. That makes up no part of our aim. We wish instead to leverage the fantastic resource that is Wikipedia and use it to create something better.

"Aha! So you are trying to outdo Wikipedia, aren't you?

"Well, of course. Why else would we be proposing a fork?"

By "fork," Citizendium means it will replicate the database of articles on Wikipedia, which uses open-source code. It will then evolve into a new encyclopedia as expert participants post their material.

Sanger and Wikipedia co-founder Jimmy Wales launched the original online encyclopedia in 2001 and it quickly became one of the most popular research tools on the web. It now contains more than two million articles in 229 languages, all written by volunteer contributors.

According to research firm Nielsen NetRating, last month Wikipedia saw more than 33 million unique visitors, up 162 per cent from the same period a year earlier.

But its popularity hasn't come without controversy over the accuracy of its articles. Last fall, an entry on John Seigenthaler, a former aide to Robert F. Kennedy, made headlines after it suggested he had been involved in the presidential candidate's assassination. This summer, comedian Stephen Colbert encouraged television viewers to make whimsical edits to the site's articles.

"You see, any user can change any entry, and if enough other users agree with them, it becomes true," Colbert said at the time.

In an attempt to discourage mischievous postings, Sanger says Citizendium will require that members register with their real name before they write for the online encyclopedia.