It's important to be critical when using websites. Make sure the information is reliable and it comes from a credible source. The website below will show you how to evaluate a website.
(From UC Berkeley)
This web site will show you how to evaluate a web site.
Questions to consider:
What can the URL tell you?
Who wrote the page?
When was the page last updated?
What are authors' credentials?
Are sources documented with footnotes?
Does it link from other pages?