A topic of continuing interest here is why and how wikipedia works (which we think it does), and so this commentary by Chris Anderson, writer for Wired, is insightful:

The Probabilistic Age:

"Q: Why are people so uncomfortable with Wikipedia? And Google? And, well, that whole blog thing?

A: Because these systems operate on the alien logic of probabilistic statistics, which sacrifices perfection at the microscale for optimization at the macroscale.

Q: Huh?

A: Exactly. Our brains aren't wired to think in terms of statistics and probability. We want to know whether an encyclopedia entry is right or wrong. We want to know that there's a wise hand (ideally human) guiding Google's results. We want to trust what we read."

And more:

"'Is Wikipedia "authoritative'? Well, no. But what really is? Britannica is reviewed by a smaller group of reviewers with higher academic degrees on average. There are, to be sure, fewer (if any) total clunkers or fabrications than in Wikipedia. But it's not infallible either; indeed, it's a lot more flawed that we usually give it credit for.

Britannica's biggest errors are of omission, not commission. It's shallow in some categories and out of date in many others. And then there are the millions of entries that it simply doesn't--and can't, given its editorial process--have. But Wikipedia can scale to include those and many more. Today Wikipedia offers 860,000 articles in English - compared with Britannica's 80,000 and Encarta's 4,500. Tomorrow the gap will be far larger."

As Anderson writes, a lot of people struggle with the (lack of) authoritativeness of what they read in a wikipedia or blog or other online collaborative effort (compared to the iron clad authoritativeness of what else, exactly, I often think?) But, says Anderson, while there may be flaws at the micro level, there is also amazing value and efficiency at the macro level.