Finding Authoritative Sources

Often I find that the first stage of a research project involves bringing myself up to speed on a subject. Linda Cooper, an information consultant in Pennsylvania, once referred to this step as "I am my own end user", meaning her initial search is often for her own use, and not for her client.
Fortunately, we have a number of surprisingly reliable, free ready-reference sources that we can tap. A couple I use frequently are Wikipedia and Answers.com.

The Wikipedia is addictive. Each article is full of links ..., and once you start clicking, there goes an hour of your day.

Wikipedia is a free encyclopedia, written and edited by volunteers. There have been many debates about the relative value of the Wikipedia and commercial encyclopedias. Most of the focus has been on the fact that the structure of the Wikipedia (like any other wiki, or collaboratively-created document) allows anyone to change an existing article and, with some limitations, to create a new article. Fortunately, the Wikipedia is "tended" by a number of editors. People who have authored articles may also monitor changes to their material, which serves as a quick correction to changes that are wrong or malicious.
More background on how the Wikipedia works may be found in this Wikipedia article. And this month's issue of Wired magazine has an article on the Wikipedia.
While I take anything I read in the Wikipedia with a grain of salt, I do the same for any other reference source. I had a project a while ago that involved the market for tungsten. Turning myself into my own end user, as Linda would say, I realized I first had to figure out what the metal was, and how it was used. I headed over to Wikipedia, and bingo! The Wikipedia article gave me plenty of background information, so I could head off to other sources to get the information my client needed.
There's a lot of intelligence built into the Wikipedia. I was looking for information on a breed of dog that a friend thinks may be part of my puppy's very mixed parentage, so I typed "viszla" in the search box. Happily, I was redirected to the article on Vizslas, a Hungarian hunting dog. And if you search for "Mercury," you will be shown a "disambiguation" page, which lists several entries for the term, Mercury, including the planet, the element, the car, and even the singer, Freddie Mercury.
But be warned: The Wikipedia is addictive. Each article is full of links to related concepts, and once you start clicking, there goes an hour of your day.
The other ready-reference site I use frequently is Answers.com, formerly the fee-based GuruNet. While the site offers some plug-ins that I don't use, its main strength is in providing quick answers. Interestingly, just today they announced a new feature, which lets you query it without going to the search page. Just enter the URL in the browser address line, followed by the topic you want to search -- for example, answers.com/tungsten.