Do you know a better free-web-site encyclopedia that wikipedia.com?

No, because wikipedia is the only trusty enough encyclopedia. Even though i knew it had issues with people fixing pages. Try searching yahoo or googling.

No.

Check out this website. It has tons and tons of information, as well as search boxes for many informational websites:

http://www.refdesk.com/

Wikipedia.com doesn't exist except as one of those useless publicity pages that have nothing to do with their title, and any encyclopedia is better than that.
If you were referring to Wikipedia.org, as is obvious you were, then no. You have to understand it's hard to match the effort of millions, and I know you're thinking "and the vandalism of millions" but no, people undo disruptions to Wikipedia and thus preserve it in a good state. Any articles that are unreferenced may be unreliable though, so always check for references when using Wikipedia.

Wikipedia is the largest encyclopedia on the Internet, and the 6th or 7th most popular website on the Internet, you'd be hard pressed to find competition. Citizendium, which was started by a Wikipedia co-founder, is on the rise though.