Wikipedia is the online encyclopedia that "anyone can edit." Unless you want to edit the entries on Albert Einstein, human rights in China or Christina Aguilera. Wikipedia's come-one, come-all invitation to write and edit articles, and the surprisingly successful results, have captured the public imagination. But it is not the experiment in freewheeling collective creativity it might seem to be, because maintaining so much openness inevitably involves some tradeoffs. "As Wikipedia has tried to improve its quality, it's beginning to look more and more like an editorial structure," said Nicholas Carr, a technology writer who recently criticized Wikipedia on his blog. "To say that great work can be created by an army of amateurs with very little control is a distortion of what Wikipedia really is."