Wikipedia is an encyclopædia built using a set of web authoring tools called a wiki, authored by countless volunteer contributors. First and foremost, it's a pretty good encyclopædia, so if I need to know when and where Harry S Truman was born, I can look it up there. If you need an encyclopædia-style précis on something, it's usally a much better source than a general web search like Google.
The article coverage is astonishingly broad. Most justices to the Canadian Supreme Court, for instance, have at least a brief listing. But the depth of articles can be a little random, and subjects of nerdy interest tend to get better coverage. For instance, the entry for the trumpeter swan is good enough, but quite brief, while there's rather more about using reverse polish notation for arithmetic, and the page on Gundam is very elaborate, with links to numerous supporting pages.
Gundam is one of the longest running meta-series of anime featuring giant robots. Gundam is the collective term for the Universal Century (UC) series like Mobile Suit Gundam and series in alternative timelines, such as Gundam Wing, made by Sunrise Inc.. The name "Gundam" itself stems from a variety of theoretical sources, most commonly attributed to a need to conform with common giant robot naming conventions during the 1970s.This is one consequence of the fact that anyone can create or edit any page. Subjects that draw the attention of folks with obsessive interests, time on their hands, and a willingness to dig into web authoring tools are more likely to get more material --- hence the completeness of nerd-oriented entries.
Another, more important, consequence of this shared authoring is how Wikipedia handles controversial subjects. You would think that if anyone can edit any page, some subjects would be intractable. Who's going to write the entry on abortion? Surprisingly, it turns out that Wikipedia is actually a very useful resource on those kinds of subjects, because it becomes a place where folks can agree about the nature of the disagreement. This is a result of some clever structuring of the editing process, which keeps articles from collapsing in the face of rapid churn from partisans, and because of a philosophical commitment to what wikipedians call the "neutral point of view."
Articles should be written without bias, representing all majority and significant minority views fairly. This is the neutral point of view policy.This approach has big advantages and big disadvantages. The advantages are pretty obvious, but the disadvantages are serious. This approach is the root of the "Opinions on Shape of Earth Differ" problem in the press corps. Wikipedia's vigorous statement of this as policy is a kind of strategic retreat on the question of objective fact, and I leave an analysis of this being a reflection of the postmodern condition as an exercise for the reader.
The policy is easily misunderstood. It doesn't assume that writing an article from a single, unbiased, objective point of view is possible. Instead it says to fairly represent all sides of a dispute by not making articles state, imply, or insinuate that only one side is correct. Crucially, a great merit of Wikipedia is that Wikipedians work together to make articles unbiased.
Writing unbiased text requires practice. Contributors who have mastered the art of NPOV are invited to help develop the neutrality tutorial.
It may be tempting at times to 'balance' a perceivedly biased article by creating an additional article on the same subject but biased the other way. Such articles are often referred to as "POV forks". Please do not do this. Instead, consider joining discussion (or requesting comments) on the biased article to make it represent all sides fairly.
I find that the upshot of this is that Wikipedia does not deliver the last word on controversial subjects, but it provides a very useful first word for getting yourself oriented. When I encounter folks who have just stepped into the dangerous waters of the history of Israel, I point them at the now-legendary Wikipedia resources on the Arab-Israeli conflict and Israeli-Palestinian conflict.
There are other group web encyclopædia efforts, of course, though none so successful. I'm a bit of a fan of Everything2, which started at an attempt at an encyclopædia but quickly evolved into a forum for odd personal essays about things like sea monkeys, the low-intensity conflict between the sexes, and the virtues of soy. There are lots of serious essays, too, but it just doesn't function an encyclopædia.
Taking a different tack, the Uncyclopedia harnesses that impulse toward whimsy in a parody of the Wikipedia, built using the same tools, that is nothing more than a massive edifice of pointless fiction. For instance, the entry on Lord Byron summarizes his career thus ...
George "Flash" Gordon Byron XII aka The Byronic Man, more commonly known as Lord Byron, was a landlord, poet, crack addict, dolphin trainer, cross-dresser, community college graduate, and, most notably, Oscar Wilde's fiercest rival.... and goes on to explain the Byronic Hero ...
The Byronic Hero is two pounds of thinly sliced turkey, honey-glazed ham, cannabis, salami, marijuana, and cheese on rye and is typically served with some of those cute party toothpicks with little olives on the end. It is usually characterised by rebellion and a distaste for society, yet a haughty appreciation for tasty lunchmeats and hallucinogenic drugs.Some people have too much free time on their hands.
Just as Wikipedia offers advice on the neutral point of view, Uncyclopedia offers some good advice on how to be funny and not stupid when creating a new article. But as with the Wikipedia advice, that this advice about humour is necessary is a sign of the issues which the Uncyclopedia is struggling with.