From Citizendium's Main Page:
"The Citizendium (sit-ih-ZEN-dee-um), a "citizens' compendium of everything," is an experimental new wiki project. The project, started by a co-founder of Wikipedia, aims to improve on that model by adding "gentle expert oversight" and requiring contributors to use their real names."
I like Citizendium because of the expert-guidance of collaboratively written science articles -- the feeling of confidence that gives in reading an article. I like the opportunity to edit articles in progress when I have something to contribute. I like the opportunity to start new articles from scratch and develop them offline before posting and giving other experts the opportunity to comment and edit. I like the fact that 'approved' articles have an accompanying 'draft' version to continue working on, eventually to replace the earlier 'approved' version -- science does not stand still.
"Share your knowledge. It's a way to achieve immortality." --Attributed to Dalai Lama