Web Sites, how do you know if they are reliable?

Hi,
   Seriously how do you know if a source is reliable.

http://www.ushmm.org/wlc/en/article.php?ModuleId=10005143

   I believe that this web site above is a very reliable source. Although this site does not have an author, it is from the United States Holocaust Memorial Museum.  If you had any questions you could directly call the museum. The article is very informative and ful of detail. At the bottom of the page is a list of sources, and related links that helped the museum give as much acurate information about the topic as is needed. The balance of photographs and informationis almost equal, however their is more information than pictures, which is what there should be. Lastly, there are no advertisments on this page, which tells you that this site is only interested in giving proper, accurate information rather than selling the reader something.

  Cathy