Are you looking for focused and complete information on something rather than having to cull it out from thousands, even million, of pages spewed out by a search engine? Just head for http://en.wikipedia.org on your browser. The site is probably the most comprehensive encyclopedia on the web or off it. In fact part of the name comes from the word encyclopedia. The first part, namely wiki, has Hawaiian roots where “wiki wiki” means quickly. Today the term wiki has come to mean any site where content can be quickly created and edited by any visitor. As many people put it, it is the most extreme form of collaboration.
When you visit the site, the default Main_page contains several sections apart from the search box which is the prime target of most visitors. The page has a featured article, a featured photo, news headlines and a couple of other sections. Interestingly one of the items on the navigation menu lets an user go to a randomly selected article.
Whichever article in the wikipedia you might navigate to, you will find four page stubs displayed with the ‘project page’ opened by default. One of the other 3 pages is ‘edit this page’. Only on a few pages will you find this stub replaced by ‘view source’ indicating that the page is protected. That the pages have not been vandalized or trolled or defaced despite the open nature of the project, initially comes as a big surprise.
A very useful feature of wikipedia is its disambiguation pages. One of these appears when the searched term may have multiple meanings. You may try searching for ATM to see a disambiguation page.
If you wish to contribute to the project, you may register for the same, though it is not mandatory. However contributions by non-registered collaborators are tracked through their IP address.