More and more resources that I would imagine as regular Web sites are now getting Wiki-ized. Wikinvest, at http://www.wikinvest.com/, provides stock information as Wiki. It’s not comprehensive (looks like about 275 companies are listed), but makes good use of the format.
From the front page you can browse company names or concepts (concepts, for the most part, appear to be industries.), but you can also do a search. As I noted, the stock list is not complete — IAC and LOOK do not have articles here. I did a search for YHOO and did get an article page. The Yahoo Page had an overview of the company, several charts related to its growth, usage, and revenue, and a list of related articles and stocks.
An interesting use of the Wiki format is the “Bulls & Bears” section. Bulls can list/edit ways that Yahoo is good investment, while Bears can do the opposite. Stock charts can be annotated with news/releases to show events that have had an impact on the stock price.
The concept pages are similar to the individual stock pages, except of course they don’t include stock charts. However they do include places for bullish and bearish comments and charts relevant to that industry. Not all industries are available, either — I didn’t see anything for mobile advertising, for example.
Editing the wiki requires absolutely no registration — IP addresses will be recorded for anonymous edits. To get a sense of what’s available here you can browse the listed companies or check out the concepts.